Transmission apparatus, reception apparatus, transmission method, and reception method

ABSTRACT

A transmission apparatus according to the present disclosure includes a plurality of user modulated signal generators. A user #k modulated signal generator (104_k) (where k=1 to n) generates a modulated signal including reference signals for phase noise estimation (PT-RS: Reference Signal for Phase Tracking), for a plurality of reception apparatuses. A wireless unit (109_A, 109_B) transmits the generated modulated signal. A correction coefficient of transmission power for the reference signals is associated with a pattern of a sequence used as the reference signals, on a one-to-one basis.

TECHNICAL FIELD

The present disclosure relates to a transmission apparatus, a receptionapparatus, a transmission method, and a reception method.

BACKGROUND ART

In wireless communication systems, phase noise occurs in modulationsignals, in relation to precision of signals generated by oscillatorsthat a transmission apparatus and reception apparatus have. For example,in NPL 1, a transmission apparatus transmits pilot symbols (alsoreferred to as reference signals) to a reception apparatus to estimatephase noise.

FIG. 1 illustrates an example frame confirmation of a modulated signalthat the transmission apparatus disclosed in NPL 1 transmits. In FIG. 1,the horizontal axis is frequency (carrier number), with carrier 1through carrier 36 illustrated as an example. The vertical axis is time,illustrating time $1 through time $11, as one example.

In FIG. 1, channel estimation symbols 01 are mapped to carrier 1 throughcarrier 36 at time $1. Also, pilot symbols 03 are mapped to carrier 4,carrier 10, carrier 16, carrier 21, carrier 28, and carrier 33 at time$2 through time $11. Also, data symbols 02 are mapped to carriers otherthan carrier 4, carrier 10, carrier 16, carrier 21, carrier 28, andcarrier 33, at time $2 through time $11.

The transmission apparatus transmits the modulated signal of the frameconfiguration illustrated in FIG. 1 to a reception apparatus that is acommunication partner. And the reception apparatus receives themodulated signal and estimates phase noise by using pilot symbols 03, inparticular.

CITATION LIST Non Patent Literature

NPL 1: IEEE P802.11n (D3.00) Draft STANDARD for InformationTechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements—Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)specifications, 2007.

SUMMARY OF INVENTION

However, this does not take into consideration that there are aplurality of reception apparatuses that are communication partners ofthe transmission apparatus described above. Further, a transmissionmethod of reference signals for estimating phase noise with goodprecision at each of the a plurality of reception apparatuses to has notbeen studied.

An aspect of the present disclosure provides a transmission apparatus,reception apparatus, transmission method, and reception method, where aplurality of communication partners can estimate phase noise with goodprecision.

A transmission apparatus according to the aspect of the presentdisclosure includes: a circuit that generates a modulated signalincluding reference signals for phase noise estimation, for a pluralityof reception apparatuses, where a correction coefficient of transmissionpower for the reference signals is associated with a pattern of asequence used as the reference signals, on a one-to-one basis; and atransmitter that transmits the modulated signal.

A reception apparatus according to the aspect of the present disclosureincludes: a receiver that receives a modulated signal includingreference signals for phase noise estimation, for a plurality ofreception apparatuses, where a correction coefficient of transmissionpower for the reference signals is associated with a pattern of asequence used as the reference signals, on a one-to-one basis; and acircuit that estimates phase noise using the reference signals for theplurality of reception apparatuses included in the modulated signal.

It should be noted that these general or specific embodiments may beimplemented as a system, an apparatus, a method, an integrated circuit,a computer program, or a computer-readable recording medium, and may berealized by any combination of a system, apparatus, method, integratedcircuit, computer program, and recording medium.

According to an aspect of the present disclosure, a plurality ofcommunication partners can estimate phase noise with good precision.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a frame configuration ofa modulated signal.

FIG. 2 is a diagram illustrating an example of a communication statebetween a base station and terminal according to a first embodiment.

FIG. 3 is a block diagram illustrating a configuration example of atransmission apparatus according to the first embodiment.

FIG. 4 is a block diagram illustrating an internal configuration exampleof a user #k modulated signal generator 104_k according to the firstembodiment.

FIG. 5A is a diagram illustrating an example of the frame configurationof data symbols, DM-RS symbols, and PT-RS symbols of a stream #X1according to the first embodiment.

FIG. 5B is a diagram illustrating an example of the frame configurationof data symbols, DM-RS symbols, and PT-RS symbols of a stream #X2according to the first embodiment.

FIG. 6 is a block diagram illustrating an inner configuration example ofwireless units 109_A and 109_B according to the first embodiment.

FIG. 7 is a diagram illustrating the frame configuration example of amodulated signal 108_A according to the first embodiment.

FIG. 8 is a diagram illustrating the frame configuration example of amodulated signal 108_B according to the first embodiment.

FIG. 9 is a block diagram illustrating a configuration example of areception apparatus according to the first embodiment.

FIG. 10 is a diagram illustrating an example of constellation pointlayout in an I-Q plane for BPSK.

FIG. 11 is a diagram illustrating an example of constellation pointlayout in an I-Q plane for QPSK.

FIG. 12 is a diagram illustrating an example of constellation pointlayout in an I-Q plane for 16QAM.

FIG. 13 is a diagram illustrating an example of constellation pointlayout in an I-Q plane for 64QAM.

FIG. 14 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 15 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 16 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 17 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 18 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 19 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 20 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 21 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 22 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 23 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 24 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 25 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 26 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_A according to the firstembodiment.

FIG. 27 is a diagram illustrating another example of the frameconfiguration of modulated signal 108_B according to the firstembodiment.

FIG. 28 is a block diagram illustrating a configuration example of atransmission apparatus according to a second embodiment.

FIG. 29 is a diagram illustrating an example of the frame configurationof a stream according to the second embodiment.

FIG. 30 is a diagram illustrating an example of the frame configurationof modulated signals according to the second embodiment.

FIG. 31 is a diagram illustrating an example of the frame configurationof DM-RS symbols according to the second embodiment.

FIG. 32 is a diagram illustrating an example of the frame configurationof DM-RS transmission region to the second embodiment.

FIG. 33 is a diagram illustrating an example of the configuration ofDFT-s-OFDM symbols according to the second embodiment.

FIG. 34 is a diagram illustrating an example of the configuration ofDFT-s-OFDM transmission region according to the second embodiment.

FIG. 35 is a diagram illustrating an example of the signal configurationafter addition of a cyclic prefix according to the second embodiment.

FIG. 36 is a diagram illustrating an example of the frame configurationof signals after addition of a cyclic prefix according to the secondembodiment.

FIG. 37 is a diagram illustrating an example of the frame configurationof signals after addition of an extended cyclic prefix according to thesecond embodiment.

FIG. 38 is a diagram illustrating an example of the frame configurationof signals after addition of a cyclic prefix according to the secondembodiment.

FIG. 39 is a diagram illustrating another example of the configurationof DFT-s-OFDM symbols according to the second embodiment.

FIG. 40 is a diagram illustrating another example of the DFT-s-OFDMtransmission region configuration according to the second embodiment.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail belowwith reference to the drawings. Note that each of the embodimentsdescribed below is an example, and the present disclosure is notrestricted by these embodiments.

Note that in the following a reference signal for estimating phase noisewill be described as PT-RS (Reference Signal for Phase Tracking), and areference signal for data demodulation will be referred to as DM-RS(Demodulation Reference Signal).

First Embodiment

A transmission apparatus, reception apparatus, transmission method, andreception method, according to the present disclosure, will be describedin detail.

[Example of Communication State]

FIG. 2 illustrates an example of the communication state between a basestation (transmission apparatus) and a terminal (reception apparatus)according to the present embodiment. A base station 401 illustrated inFIG. 2 has the configuration of a later-described transmission apparatus(FIG. 3), for example. Also, terminals 402_1, 402_2, and 402_3illustrated in FIG. 2, have the configuration of a later-describedreception apparatus (FIG. 9), for example.

For example, the base station 401 transmits modulated signals to theterminals 402_1, 402_2, and 402_3. The terminals 402_1, 402_2, and 402_3estimate phase noise using the PT-RS included in the modulated signalstransmitted from the base station 401.

[Configuration of Transmission Apparatus]

FIG. 3 is a block diagram illustrating a configuration example of atransmission apparatus according to the present embodiment. Thetransmission apparatus illustrated in FIG. 3 is, for example, the basestation 401 illustrated in FIG. 2, an access point, or the like.

In FIG. 3, a user #k modulated signal generator 104-k (where k is aninteger of 1 or greater but 3 or smaller, for example) takes input ofdata 101_k, DM-RS 102_k, PT-RS 103_k, and control signals 100. The user#k modulated signal generator 104-k generates and outputs modulatedsignals 105_k and 106_k of the user #k, based on information regardingthe frame configuration, modulation scheme, error correction encodingmethod, and so forth, included in the control signals 100.

A control information mapping unit 113 takes input of controlinformation 112 and control signals 100, performs mapping for thecontrol information 112 based on information such as frame configurationand the like included in the control signals 100, and outputs controlinformation signals 114.

A multiplexer (signal processing unit) 107_A takes input of a modulatedsignal 105_1 of user #1, a modulated signal 105_2 of user #2, . . . , amodulated signal 105_n-1 of user #n-1, a modulated signal 105_n of user#n, control signals 100 and control information signals 114. Themultiplexer 107_A generates and outputs modulated signals 108_Afollowing the frame configuration, based on the information such asframe configuration and so forth included in the control signals 100.

In the same way, a multiplexer (signal processing unit) 107_B takesinput of a modulated signal 106_1 of user #1, a modulated signal 106_2of user #2, . . . , a modulated signal 106_n-1 of user #n-1, a modulatedsignal 106_n of user #n, control signals 100 and control informationsignals 114. The multiplexer 107_B generates and outputs a modulatedsignal 108_B following the frame configuration, based on the informationsuch as frame configuration and so forth included in the control signals100.

A wireless unit 109_A takes as input the modulated signal 108_Afollowing the frame format, and the control signals 100. The wirelessunit 109_A performs wireless-related processing on the modulated signal108_A, and generates transmission signal 110_A, in accordance with thecontrol signal 100. The transmission signal 110_A is output as radiowaves from an antenna unit #A (111_A).

In the same way, a wireless unit 109_B takes as input the modulatedsignal 108_B following the frame format, and the control signal 100. Thewireless unit 109_B performs wireless-related processing on themodulated signal 108_B, and generates a transmission signal 110_B, inaccordance with the control signal 100. The transmission signal 110_B isoutput as radio waves from an antenna unit #B (111_B).

The antenna unit #A (111_A) takes the control signals 100 as input. Theantenna unit #A (111_A) may perform transmission directionality controlfollowing the control signals 100. The antenna unit #A (111_A) does nothave to have the control signals 100 as input. In the same way, theantenna unit #B (111_B) takes the control signals 100 as input. Theantenna unit #B (111_B) may perform transmission directionality controlfollowing the control signals 100. The antenna unit #B (111_B) does nothave to have the control signals 100 as input.

[Configuration Example of User #k Modulated Signal Generator 104-k]

FIG. 4 is a block diagram illustrating an internal configuration exampleof the user #k modulated signal generator 104-k illustrated in FIG. 3.

In FIG. 4, an error correction encoder 203 takes data 201 (equivalent tothe data 101_k in FIG. 3) and a control signal 200 (equivalent to thecontrol signals 100 in FIG. 3) as input. The error correction encoder203 performs error correction encoding on the data 201 based oninformation relating to the error correction encoding format included inthe control signal 200 (e.g., information of error correction encoding,code rate, block length, etc.) and so forth, and outputspost-error-correction-encoding data 204.

A mapping unit 205 takes the post-error-correction-encoding data 204 andcontrol signal 200 as input. The mapping unit 205 performs mapping forthe post-error-correction-encoding data 204 based on the modulationscheme information included in the control signal 200, and outputspost-mapping baseband signals 206_1 and 206_2. Note that in thefollowing, the post-mapping baseband signals 206_1 will be referred toas stream #X1, and the post-mapping baseband signals 206_2 will bereferred to as stream #X2.

A processing unit 207 takes as input the post-mapping baseband signals206_1 and 206_2, a DM-RS 202 (equivalent to the DM-RS 102_k in FIG. 3),a PT-RS (equivalent to the PT-RS 103_k in FIG. 3), and the controlsignal 200. The processing unit 207 performs predetermined processing(e.g., precoding, changing transmission power, CDD (CSD), and likeprocessing), based on information relating to the frame configurationincluded in the control signal 200, information relating to precoding,information of transmission power, information relating to CDD (CyclicDelay Diversity) (CSD (Cyclic Shift Diversity)), and so forth, andoutputs modulated signal 208_A (equivalent to the modulated signal 105_kin FIG. 3) and 208_B (equivalent to the modulated signal 106_k in FIG.3).

In the following, the modulated signal 208_A will be expressed as“u1(i)”, and the modulated signal 208_B will be expressed as “u2(i)”.Note that i is a symbol number.

When performing precoding processing, the processing unit 207 may switchprecoding (matrix) used in precoding processing in increments of aplurality of symbols, and may perform precoding cycling processing whereof switching precoding (matrix) used in precoding processing inincrements of symbols. Alternatively, the processing unit 207 does nothave to perform precoding processing.

[Example Frame Configuration of Modulated Signals]

FIG. 5A illustrates an example of the frame configuration ofpost-mapping baseband signal 206_1 after mapping by the mapping unit 205in FIG. 4 (i.e., data symbols of the stream #X1), DM-RS symbols of thestream #X1 added to the data symbols of the stream #X1, and PT-RSsymbols of stream #X1. Note that the user # is k.

In FIG. 5A, the horizontal axis is frequency (carrier number),illustrating carrier k_1 to carrier k_12 as an example. The verticalaxis in FIG. 5A is time, illustrating time $1 through time $11 as anexample. “2B01” in FIG. 5A is the DM-RS symbol of the stream #X1, “2B02”is the data symbol of the stream #X1, and “2B03” is the PT-RS symbol ofthe stream #X1.

FIG. 5B illustrates an example of the frame configuration ofpost-mapping baseband signals 206_2 after mapping by the mapping unit205 in FIG. 4 (i.e., data symbols of the stream #X2), DM-RS symbols ofthe stream #X2 added to the data symbols of the stream #X2, and PT-RSsymbols of stream #X2. Note that the user # is k.

In FIG. 5B, the horizontal axis is frequency (carrier number),illustrating carrier k_1 to carrier k_12 as an example. The verticalaxis in FIG. 5B is time, illustrating time $1 through time $11 as anexample. “2C01” in FIG. 5B is the DM-RS symbol of the stream #X2, “2C02”is the data symbol of the stream #X2, and “2C03” is the PT-RS symbol ofthe stream #X2.

That is to say, the DM-RS 202 illustrated in FIG. 4 includes the DM-RSsymbol (2B01) of the stream #X1 and the DM-RS symbol (2C01) of thestream #X2. Also, the PT-RS 203 illustrated in FIG. 4 includes the PT-RSsymbol (2B03) of the stream #X1 and the DM-RS symbol (2C03) of thestream #X2.

The processing unit 207 generates the modulated signal 208_A of thestream #X1 based on the frame configuration illustrated in FIG. 5A basedon the frame configuration information included in the control signal200, and the modulated signal 208_B of the stream #X2 based on the frameconfiguration illustrated in FIG. 5B.

The frame is made up of the DM-RS symbol 2B01 of the stream #X1, datasymbol 2B02 of the stream #X1, and the PT-RS symbol of the stream #X1,as illustrated in FIG. 5A. Specifically, in FIG. 5A, the DM-RS symbol2B01 of the stream #X1 is positioned at time $1, the PT-RS symbol 2B03of the stream #X1 is positioned at carrier k_4 and carrier_k10 at time$2 through time $11, and the data symbol 2B02 of the stream #X1 ispositioned at carriers other than carrier k_4 and carrier_k10 at time $2through time $11.

In the same way, the frame is made up of the DM-RS symbol 2C01 of thestream #X2, data symbol 2C02 of the stream #X2, and the PT-RS symbol ofthe stream #X2, as illustrated in FIG. 5B. Specifically, in FIG. 5B, theDM-RS symbol 2C01 of the stream #X2 is positioned at time $1, the PT-RSsymbol 2C03 of the stream #X2 is positioned at carrier k_4 andcarrier_k10 at time $2 through time $11, and the data symbol 2C02 of thestream #X2 is positioned at carriers other than carrier k_4 andcarrier_k10 at time $2 through time $11.

Symbols at the same time in FIG. 5A and FIG. 5B, and of the samecarrier, are transmitted using a plurality of antenna units (111_A and111_B)

[Configuration Example of Wireless Units 109_A and 109_B]

FIG. 6 is a block diagram illustrating an internal configuration exampleof the wireless units 109_A and 109_B in FIG. 3.

In FIG. 6, a serial/parallel conversion unit 302 takes as inputmodulated signal 301 following the frame configuration (equivalent tomodulated signals 108_A or modulated signal 108_B following the frameconfiguration in FIG. 3), and a control signal 300 (equivalent to thecontrol signals 100 in FIG. 3). The serial/parallel conversion unit 302performs serial/parallel conversion of the modulated signal 301 based onthe control signal 300, and outputs signal 303.

An inverse Fourier transform unit 304 takes the signal 303 and controlsignal 300 as input. The inverse Fourier transform unit 304 subjects thesignals 303 to inverse Fourier transform based on the control signal300, and outputs post-inverse-Fourier-transform signal 305.

The processing unit 306 takes as input thepost-inverse-Fourier-transform signals 305 and control signal 300. Theprocessing unit 306 subjects the post-inverse-Fourier-transform signal305 to signal processing (e.g., CDD, CSD, or phase change or the like)based on the control signal 300, and outputs post-processing signal 307(equivalent to transmission signals 110_A or transmission signals 110_Bin FIG. 3).

Note that the processing unit 306 does not have to perform signalprocessing. In this case, the post-inverse-Fourier-transform signal 305become the post-processing signals 307 without change. Also, thewireless units 109_A and 109_B do not need to have the processing unit306. In this case, the post-inverse-Fourier-transform signals 305 arethe output of the wireless units 109_A and 109_B (i.e., equivalent totransmission signals 110_A or transmission signals 110_B). The wirelessunits 109_A and 109_B do not have to perform CDD or CSD processing.

[Example Frame Configuration of Modulated Signals 108_A and 108_B]

FIG. 7 illustrates an example of the configuration of the frameconfiguration of the modulated signal 108_A that the base station 401illustrated in FIG. 2 (transmission apparatus illustrated in FIG. 3)transmits. In FIG. 7, the horizontal axis is frequency (carrier number),with carrier 1 through carrier 36 illustrated as an example. Thevertical axis is time, illustrating time #a and time $1 through time$11.

The frame illustrated in FIG. 7 is configured of a control informationtransmission region 500, a DM-RS transmission region 501, a datatransmission region 502, and a PT-RS transmission region 503.

Now, in FIG. 7, the transmission region existing from carrier 1 throughcarrier 12 from time $1 to time $11 is a transmission region for theterminal 402_1 illustrated in FIG. 2 (transmission region directed toterminal 402_1). Hereinafter, the transmission region for the terminal402_1 will be referred to as transmission region for user #1, asillustrated in FIG. 7.

In the same way, in FIG. 7, the transmission region existing fromcarrier 13 through carrier 24 from time $1 to time $11 is a transmissionregion for the terminal 402_2 illustrated in FIG. 2 (transmission regiondirected to terminal 402_2). Hereinafter, the transmission region forthe terminal 402_2 will be referred to as transmission region for user#2, as illustrated in FIG. 7.

Also, in FIG. 7, the transmission region existing from carrier 25through carrier 36 from time $1 to time $11 is a transmission region forthe terminal 402_3 illustrated in FIG. 2 (transmission region directedto terminal 402_3). Hereinafter, the transmission region for theterminal 402_3 will be referred to as transmission region for user #3,as illustrated in FIG. 7.

Control information transmission region 500 is placed at time #a in FIG.7. The control information transmission region 500 may include forexample, the position of presence in the frame of the transmissionregion for user #1, the transmission region for user #2, and thetransmission region for user #3, information relating to the modulationscheme of each transmission region, information relating to errorcorrection encoding, information relating to precoding matrix,information relating to transmission method, and so forth. Note thatwhile the control information transmission region 500 is illustrated asbeing placed at time #a in the example in of the frame configurationFIG. 7, the position of presence of the control information transmissionregion 500 is not restricted to this, and various examples can beconceived, such as being present in one of the carriers, being presentat one of the times, being present in one of the carrier-time regions,and so forth.

In the transmission region for user #1 illustrated in FIG. 7, the DM-RStransmission region 501 is placed at time $1, the PT-RS transmissionregion 503 is placed at carrier 4 and carrier 10 at time $2 through time$11, and the data transmission region 502 is placed at carriers otherthan carrier 4 and carrier 10 at time $2 through time $11.

In the same way, in the transmission region for user #2 illustrated inFIG. 7, the DM-RS transmission region 501 is placed at time $1, thePT-RS transmission region 503 is placed at carrier 16 and carrier 21 attime $2 through time $11, and the data transmission region 502 is placedat carriers other than carrier 16 and carrier 21 at time $2 through time$11.

Also, in the transmission region for user #3 illustrated in FIG. 7, theDM-RS transmission region 501 is placed at time $1, the PT-RStransmission region 503 is placed at carrier 28 and carrier 33 at time$2 through time $11, and the data transmission region 502 is placed atcarriers other than carrier 28 and carrier 33 at time $2 through time$11.

Note that the frame configuration illustrated in FIG. 7 is one example,and the configuration of the count of carriers and time is notrestricted to the configuration illustrated in FIG. 7. Transmissionregions other than the transmission regions illustrated in FIG. 7 mayexist, and the layout of the transmission regions as to the frame is notrestricted to the configuration in FIG. 7.

Next, a frame configuration example of the modulated signal 108_B willbe described.

FIG. 8 illustrates an example of the configuration of the frameconfiguration of the modulated signal 108_B that the base station 401illustrated in FIG. 2 (transmission apparatus illustrated in FIG. 3)transmits. In FIG. 8, the horizontal axis is frequency (carrier number),with carrier 1 through carrier 36 illustrated as an example. Thevertical axis is time, illustrating time #a and time $1 through time $11

The frame illustrated in FIG. 8 is configured of a control informationtransmission region 600, a DM-RS transmission region 601, a datatransmission region 602, and a PT-RS transmission region 603.

Now, in FIG. 8, the transmission region existing from carrier 1 throughcarrier 12 from time $1 to time $11 is a transmission region for theterminal 402_1 illustrated in FIG. 2 (transmission region directed toterminal 402_1). Hereinafter, the transmission region for the terminal402_1 will be referred to as transmission region for user #1, asillustrated in FIG. 8.

In the same way, in FIG. 8, the transmission region existing fromcarrier 13 through carrier 24 from time $1 to time $11 is a transmissionregion for the terminal 402_2 illustrated in FIG. 2 (transmission regiondirected to terminal 402_2). Hereinafter, the transmission region forthe terminal 402_2 will be referred to as transmission region for user#2, as illustrated in FIG. 8.

Also, in FIG. 8, the transmission region existing from carrier 25through carrier 36 from time $1 to time $11 is a transmission region forthe terminal 402_3 illustrated in FIG. 2 (transmission region directedto terminal 402_3). Hereinafter, the transmission region for theterminal 402_3 will be referred to as transmission region for user #3,as illustrated in FIG. 8.

Control information transmission region 600 is placed at time #a in FIG.8. The control information transmission region 600 may include forexample, the position of presence in the frame of the transmissionregion for user #1, the transmission region for user #2, and thetransmission region for user #3, information relating to the modulationscheme of each transmission region, information relating to errorcorrection encoding, information relating to precoding matrix,information relating to transmission method, and so forth. Note thatwhile the control information transmission region 600 is illustrated asbeing placed at time #a in the example of the frame configuration inFIG. 8, the position of presence of the control information transmissionregion 600 is not restricted to this, and various examples can beconceived, such as being present in one of the carriers, being presentat one of the times, being present in one of the carrier-time regions,and so forth.

In the transmission region for user #1 illustrated in FIG. 8, the DM-RStransmission region 601 is placed at time $1, the PT-RS transmissionregion 603 is placed at carrier 4 and carrier 10 at time $2 through time$11, and the data transmission region 602 is placed at carriers otherthan carrier 4 and carrier 10 at time $2 through time $11.

In the same way, in the transmission region for user #2 illustrated inFIG. 8, the DM-RS transmission region 601 is placed at time $1, thePT-RS transmission region 603 is placed at carrier 16 and carrier 21 attime $2 through time $11, and the data transmission region 602 is placedat carriers other than carrier 16 and carrier 21 at time $2 through time$11.

Also, in the transmission region for user #3 illustrated in FIG. 8, theDM-RS transmission region 601 is placed at time $1, the PT-RStransmission region 603 is placed at carrier 28 and carrier 33 at time$2 through time $11, and the data transmission region 602 is placed atcarriers other than carrier 28 and carrier 33 at time $2 through time$11.

Note that the frame configuration illustrated in FIG. 8 is one example,and the configuration of the count of carriers and time is notrestricted to the configuration illustrated in FIG. 8. Transmissionregions other than the transmission regions illustrated in FIG. 8 mayexist, and the layout of the transmission regions as to the frame is notrestricted to the configuration in FIG. 8.

Also, at the time of the PT-RS transmission regions 503 and 603 forparticular carriers being laid out as illustrated in FIG. 7 and FIG. 8,the number of carriers where the PT-RS transmission regions 503 and 603are placed is not restricted to two carriers for the transmission regionof each user, and similar implementation can be carried out as long asthe PT-RS transmission regions 503 and 603 are placed at one or morecarriers. There also may be cases where the PT-RS transmission regions503 and 603 are not placed in the transmission region of a certain user.Further, a configuration may be made where the PT-RS transmissionregions 503 and 603 are placed in a certain carrier region at a certaintime.

[Relation Between Symbols and Transmission Regions]

Next, the relation between “symbols” described in FIG. 5A and FIG. 5B,and “transmission regions” described in FIG. 7 and FIG. 8 will bedescribed. Note that description will be made below regarding user #k.

The processing unit 207 illustrated in FIG. 4 also performs precodingprocessing, as described above. Signals before precoding are expressedbelow as s1(i) and s2(i), where i is the symbol number.

That is to say, the signal s1(i) before precoding includes the datasymbol of the stream #X1 (post-mapping baseband signal 206_1) (2B02),the DM-RS symbol of the stream #X1 (2B01), and the PT-RS symbol of thestream #X1 (2B03). In the same way, the signal s2(i) before precodingincludes the data symbol of the stream #X2 (post-mapping baseband signal206_2) (2C02), the DM-RS symbol of the stream #X2 (2C01), and the PT-RSsymbol of the stream #X2 (2C03).

<About Data Symbols>

Of the signals s1(i) before precoding, the data symbol of the stream #X1(2B02) is written as “sD1(i)”, and of the signals s2(i) beforeprecoding, the data symbol of the stream #X2 (2C02) is written as“sD2(i)”.

Also, of the modulated signal 208_A that is the output of the processingunit 207 illustrated in FIG. 4, the signals of the data transmissionregion 502 illustrated in FIG. 7 are written as “uD1(i)”, and of themodulated signal 208_B that is the output of the processing unit 207illustrated in FIG. 4, the signals of the data transmission region 602illustrated in FIG. 8 are written as “uD2(i)”.

The precoding matrix (of the user #k) will written as F, the matrixrelating to CDD (of the user #k) as W, and values of change in level oftransmission (power) (hereinafter “correction coefficients) as α1 andα2.

At this time, the following expressions hold. Note however, that α1 andα2 can be defined by complex numbers or real numbers, may be set foreach user, may be set in increments of a plurality of symbols, may beset in increments of symbols, or may be fixed values. Note that in acase where no change of transmission level is performed, this isexpressed as α1=α2=1, and computation of change to transmission level isnot performed in the following Expressions.

Case of performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 1} \right\rbrack & \; \\{{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {F \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}}{{Alternatively},}} & {{Expression}\mspace{14mu}(1)} \\\left\lbrack {{Math}\mspace{14mu} 2} \right\rbrack & \; \\{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times F \times \begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(2)}\end{matrix}$

Case of performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 3} \right\rbrack & \; \\{{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {W \times F \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}}{{Alternatively},}} & {{Expression}\mspace{14mu}(3)} \\{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times W \times F \times \begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(4)}\end{matrix}$

Case of not performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 5} \right\rbrack & \; \\{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(5)}\end{matrix}$

Case of not performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 6} \right\rbrack & \; \\{{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {W \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}}{{Alternatively},}} & {{Expression}\mspace{14mu}(6)} \\\left\lbrack {{Math}\mspace{14mu} 7} \right\rbrack & \; \\{\begin{pmatrix}{{uD}\; 1(i)} \\{{uD}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times W \times \begin{pmatrix}{{sD}\; 1(i)} \\{{sD}\; 2\;(i)}\end{pmatrix}}} & \;\end{matrix}$<About DM-RS Symbols>

Of the signals s1(i) before precoding, the DM-RS symbol of the stream#X1 (2B01) is written as “sDR1(i)”, and of the signals s2(i) beforeprecoding, the DM-RS symbol of the stream #X2 (2C01) is written as“sDR2(i)”.

Also, of the modulated signal 208_A that is the output of the processingunit 207 illustrated in FIG. 4, the signals of the DM-RS transmissionregion 501 illustrated in FIG. 7 are written as “uDR1(i)”, and of themodulated signal 208_B that is the output of the processing unit 207illustrated in FIG. 4, the signals of the DM-RS transmission region 601illustrated in FIG. 8 are written as “uDR2(i)”.

At this time, the following Expressions hold. Note that in a case whereno change of transmission (power) level is performed, this is expressedas α1=α2=1, and computation of change to transmission level is notperformed in the following Expressions.

Case of performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 8} \right\rbrack & \; \\{{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {F \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sD}\; R\; 1(i)} \\{{sD}\; R\; 2\;(i)}\end{pmatrix}}}{{Alternatively},}} & {{Expression}\mspace{14mu}(8)} \\\left\lbrack {{Math}\mspace{14mu} 9} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uD}\; R\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times F \times \begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2\;(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(9)}\end{matrix}$

Case of performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 10} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {W \times F \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(10)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 11} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times W \times F \times \begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(11)}\end{matrix}$

Case of not performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 12} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(1)}\end{matrix}$

Case of not performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 13} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {W \times \begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix}\begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(13)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 14} \right\rbrack & \; \\{\begin{pmatrix}{{uDR}\; 1(i)} \\{{uDR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\alpha\; 1} & 0 \\0 & {\alpha\; 2}\end{pmatrix} \times W \times \begin{pmatrix}{{sDR}\; 1(i)} \\{{sDR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(14)}\end{matrix}$<About PT-RS Symbols>

Of the signals s1(i) before precoding, the PT-RS symbol of the stream#X1 (2B03) is written as “sPR1(i)”, and of the signals s2(i) beforeprecoding, the PT-RS symbol of the stream #2 (2C03) is written as“sPR2(i)”.

Also, of the modulated signal 208_A that is the output of the processingunit 207 illustrated in FIG. 4, the signals of the PT-RS transmissionregion 503 illustrated in FIG. 7 are written as “uPR1(i)”, and of themodulated signal 208_B that is the output of the processing unit 207illustrated in FIG. 4, the signals of the PT-RS transmission region 603illustrated in FIG. 8 are written as “uPR2(i)”.

At this time, with values of change in level of PT-RS transmission(electrical power) (correction coefficients) as β1 and β2, the followingexpressions hold. That is to say, correction coefficients β1 and β2,that are different from the correction coefficients α1 and α2 fortransmission level that are applied to the data symbol and DM-RS symbol,are applied to the PT-RS symbol. Note however, that β1 and β2 can bedefined by complex numbers or real numbers, may be set for each user,may be set in increments of a plurality of symbols, may be set inincrements of symbols, or may be fixed values. Note that in a case whereno change of transmission level is performed, this is expressed asβ1=β2=1, and computation of change to transmission level is notperformed in the following Expressions.

Case of performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 15} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {F \times \begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix}\begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(15)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 16} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix} \times F \times \begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(16)}\end{matrix}$

Case of performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 17} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {W \times F \times \begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix}\begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(17)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 18} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix} \times W \times F \times \begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(18)}\end{matrix}$

Case of not performing precoding and not performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 19} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix}\begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(19)}\end{matrix}$

Case of not performing precoding and performing CDD:

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 20} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {W \times \begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix}\begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}(20)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 21} \right\rbrack & \; \\{\begin{pmatrix}{{uPR}\; 1(i)} \\{{uPR}\; 2(i)}\end{pmatrix} = {\begin{pmatrix}{\beta\; 1} & 0 \\0 & {\beta\; 2}\end{pmatrix} \times W \times \begin{pmatrix}{{sPR}\; 1(i)} \\{{sPR}\; 2(i)}\end{pmatrix}}} & {{Expression}\mspace{14mu}\left( {2l} \right)}\end{matrix}$

Note that in Expression (1) through Expression (21), a case where theprecoding matrix used for obtaining signals in the PT-RS transmissionregion and the precoding matrix used for obtaining signals in the datatransmission region and signals in the DM-RS transmission region are thesame matrix is described, but different matrices may be used.

Also, the following is conceivable as an example of the precoding matrixF.

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 22} \right\rbrack & \; \\{F = \begin{pmatrix}a & b \\c & d\end{pmatrix}} & {{Expression}\mspace{14mu}(22)}\end{matrix}$

In Expression (22), a, b, c, and d can be defined by complex numbers orreal numbers. It is sufficient for the conditions of a, b, c, and d tosatisfy any one of the following conditions <1> through <4>.

<1> a, b, c, and d are never all zero.

<2> Three or more of a, b, c, and d are never zero.

<3> Two or more of a, b, c, and d are never zero.

<4> Two or more of a, b, c, and d are never zero, a=c=0 is neversatisfied, and b=d=0 is never satisfied.

The following is conceivable for an example of a matrix relating to CDD.

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 23} \right\rbrack & \; \\{W = \begin{pmatrix}p & q \\r & s\end{pmatrix}} & {{Expression}\mspace{14mu}(23)}\end{matrix}$

In Expression (23), p, q, r, and s can be defined by complex numbers orreal numbers. It is sufficient for the conditions of p, q, r, and s tosatisfy any one of the following conditions <5> through <8>.

<5> p=e^(jθ), and q=0, and r=0, and s=e^(jλ)

where p and s are set for each symbol.

<6> p=g×e^(jθ), and q=0, and r=0, and s=h×e^(jλ)

where p and s are set for each symbol, and g and h are real numbers.

<7> p=0, and q=e^(jθ), and r=e^(jλ), and s=0

where p and s are set for each symbol.

<8> p=0, and q=g×e^(jθ), and r=h×e^(jλ), and s=0 where p and s are setfor each symbol, and g and h are real numbers.

[Configuration Example of Reception Apparatus]

FIG. 9 is a block diagram illustrating a configuration example of areception apparatus according to the present embodiment. The receptionapparatus illustrated in FIG. 9 is the terminals 402_1, 402_2. And 402_3that are the communication partners with the base station 401 (thetransmission apparatus illustrated in FIG. 3) illustrated in FIG. 2, forexample.

Note that in the following, in the transmission apparatus illustrated inFIG. 3, a modulated signal transmitted from the antenna unit #A (111_A)will be referred to as “modulated signal u1”, and a modulated signaltransmitted from the antenna unit #B (111_B) will be referred to as“modulated signal u2”

A wireless unit 703X takes a reception signal 702X received at anantenna unit #X (701X) as input. The wireless unit 703X subjects thereception signal 702X to signal processing such as frequency conversion,Fourier transform, and so forth, and outputs a baseband signal 704X.

In the same way, a wireless unit 703Y takes a reception signal 702Yreceived at an antenna unit #Y (701Y) as input. The wireless unit 703Ysubjects the reception signal 702Y to signal processing such asfrequency conversion, Fourier transform, and so forth, and outputs abaseband signal 704Y.

A control information demodulator 709 takes the baseband signals 704Xand 704Y as input. The control information demodulator 709 extractscontrol information symbols (e.g., the control information transmissionregion 500 illustrated in FIG. 7 and the control informationtransmission region 600 illustrated in FIG. 8), demodulates thesecontrol information symbols (control information transmission regions),and outputs control information 710.

The antenna unit #X (701X) and the antenna unit #Y (701Y) take thecontrol information 710 as input. The antenna unit #X (701X) and theantenna unit #Y (701Y) may perform reception directionality controlfollowing the control information 710. Also, the antenna unit #X (701X)and the antenna unit #Y (701Y) do not have to have the controlinformation 710 as input.

A modulated signal u1 channel estimating unit 705_1 takes the basebandsignal 704X and control information 710 as input. The modulated signalu1 channel estimating unit 705_1 performs channel estimation of themodulated signal u1 using the DM-RS transmission region 501 illustratedin FIG. 7 and/or the DM-RS transmission region 601 illustrated in FIG.8, and outputs channel estimation signal 706_1 for the modulated signalu1.

In the same way, a modulated signal u1 channel estimating unit 707_1takes the baseband signal 704Y and control information 710 as input. Themodulated signal u1 channel estimating unit 707_1 performs channelestimation of the modulated signal u1 using the DM-RS transmissionregion 501 illustrated in FIG. 7 and/or the DM-RS transmission region601 illustrated in FIG. 8, and outputs a channel estimation signal 708_1for the modulated signal u1.

A modulated signal u2 channel estimating unit 705_2 takes the basebandsignal 704X and control information 710 as input. The modulated signalu2 channel estimating unit 705_2 performs channel estimation of themodulated signal u2 using the DM-RS transmission region 501 illustratedin FIG. 7 and/or the DM-RS transmission region 601 illustrated in FIG.8, and outputs a channel estimation signal 706_2 for the modulatedsignal u2.

In the same way, a modulated signal u2 channel estimating unit 707_2takes the baseband signal 704Y and control information 710 as input. Themodulated signal u2 channel estimating unit 707_2 performs channelestimation of the modulated signal u2 using the DM-RS transmissionregion 501 illustrated in FIG. 7 and/or the DM-RS transmission region601 illustrated in FIG. 8, and outputs a channel estimation signal 708_2for the modulated signal u2.

A phase noise estimating unit 711 takes the baseband signal 704X andcontrol information 710 as input. The phase noise estimating unit 711estimates phase noise using the PT-RS transmission region 503 and/orPT-RS transmission region 603, and outputs a phase noise estimationsignal 712.

In the same way, a phase noise estimating unit 713 takes the basebandsignal 704Y and control information 710 as input. The phase noiseestimating unit 713 estimates phase noise using the PT-RS transmissionregion 503 and/or PT-RS transmission region 603, and outputs a phasenoise estimation signal 714.

A signal processing unit 715 takes as input channel estimation signals706_1 and 708_1 of the modulated signal u1, channel estimation signals706_2 and 708_2 of the modulated signal u2, the phase noise estimationsignals 712 and 714, the baseband signals 704X and 704Y, and controlinformation 710. The signal processing unit 715 uses these signals toperform processing such as demodulation, error correction decoding, andso forth, on the data symbols (data transmission regions 502 and 602),and outputs a reception signal 716.

[Phase Noise Estimation Method]

Next, the estimation method of phase noise performed at the receptionapparatus illustrated in FIG. 9 will be described.

As one example, the problems at the time of estimating phase noise withhigh precision at the terminal 402_2 (user #2) illustrated in FIG. 2will be described.

The frame configuration of modulated signals that the base station 401illustrated in FIG. 2 (the transmission apparatus illustrated in FIG. 3)transmits is as described in FIG. 7 and FIG. 8. The following twomethods 1 and 2 are conceivable as methods for the terminal 402_2 (thereception apparatus illustrated in FIG. 9) to estimate phase noise.

<Method 1>

In method 1, the terminal 402_2 estimates phase noise using PT-TSsymbols directed to itself in FIG. 5A and FIG. 5B (2B03 and 2C03), i.e.,using the PT-RS transmission region 503 for user #2 in carrier 16 andcarrier 21 illustrated in FIG. 7, and the PT-RS transmission region 603for user #2 in carrier 16 and carrier 21 illustrated in FIG. 8.

<Method 2>

In method 2, the terminal 402_2 estimates phase noise using PT-RSsymbols directed to other terminals in addition to the PT-RS symbolsdirected to itself in FIG. 5A and FIG. 5B (2B03 and 2C03).

That is to say, the terminal 402_2 estimates phase noise using “thePT-RS transmission region 503 for another user in carrier 4, carrier 10,carrier 28, and carrier 33 illustrated in FIG. 7”, and “the PT-RStransmission region 603 for another user in carrier 4, carrier 10,carrier 28, and carrier 33 illustrated in FIG. 8”, in addition to “thePT-RS transmission region 503 for user #2 in carrier 16 and carrier 21illustrated in FIG. 7, and the PT-RS transmission region 603 for user #2in carrier 16 and carrier 21 illustrated in FIG. 8”.

Methods 1 and 2 for estimating phase noise at the terminal 402_2 havebeen described.

There is a possibility that using the method 2 at the terminal 402_2(reception apparatus) can improve the estimation precision of phasenoise using a greater number of PT-RS than the method 1. Accordingly, amethod for realizing phase noise estimation by the method 2 will bedescribed below in detail.

In the frame configuration indicated in FIG. 7 and FIG. 8, the basestation 401 (transmission apparatus) adjusts the transmission power ofat least data symbols (data transmission region) of the user #1 inaccordance with the state of the terminal 402_1 (user #1). In the sameway, the base station 401 adjusts the transmission power of at leastdata symbols (data transmission region) of the user #2 in accordancewith the state of the terminal 402_2 (user #2), and adjusts thetransmission power of at least data symbols (data transmission region)of the user #3 in accordance with the state of the terminal 402_3 (user#3).

At this time, the base station 401 adjusts the transmission power ofPT-RS symbols (PT-RS transmission region) placed in carrier 4 andcarrier 10, to match the rules of transmission power adjustment of datasymbols for the user #1. In the same way, the base station 401 adjuststhe transmission power of PT-RS symbols (PT-RS transmission region)placed in carrier 16 and carrier 21, to match the rules of transmissionpower adjustment of data symbols for the user #2, and adjusts thetransmission power of PT-RS symbols (PT-RS transmission region) placedin carrier 28 and carrier 33, to match the rules of transmission poweradjustment of data symbols for the user #3.

Note that the relation between “transmission region” in FIG. 7 and FIG.8, and “symbol” in FIG. 5A and FIG. 5B is as described above.

Now, a case where the base station 401 transmits information relating totransmission power adjudgment described above (transmission powerinformation) in a control information transmission region such as thecontrol information transmission region 500, 600, or the like, will bedescribed.

In this case, the terminal 402_2 illustrated in FIG. 2 (the receptionapparatus illustrated in FIG. 9) obtains transmission power informationof other users, i.e., the symbol transmission power information for theuser #1 and the symbol transmission power information for the user #3,from control information symbols. Accordingly, there is a highprobability that the terminal 402_2 will be able to easily use the PT-RSsymbols of the PT-RS transmission regions placed in carrier 4, carrier10, carrier 28, and carrier 33, to estimate phase noise. Thus, theterminal 402_2 can use PT-RS transmission regions (PT-RS symbols) ofother users for phase noise estimation, which is advantageous in thatreception quality of data obtained from desired data symbols can beimproved.

However, there is need to take into consideration protection of data ofother users, and increase in control information for a framework toprotect data of other users, when performing phase noise estimationusing such a method.

A method to realize phase noise estimation, that differs from theabove-described method, will be described below.

A first method will be described.

First, the base station 401 performs adjustment of transmission power ofdata symbols for the users, and transmits transmission power informationindicating the level of transmission power, using the controlinformation transmission region 500 illustrated in FIG. 7 and/or controlinformation transmission region 600 illustrated in FIG. 8, for example.

As one example, in the frame configuration in FIG. 7 and FIG. 8, thebase station 401 sets the transmission (power) level of “symbols” intransmission regions excluding the PT-RS transmission regions 503 and603 for the user #1 to “1.0”, the transmission (power) level of“symbols” in transmission regions excluding the PT-RS transmissionregions 503 and 603 for the user #2 to “4.0”, and the transmission(power) level of “symbols” in transmission regions excluding the PT-RStransmission regions 503 and 603 for the user #3 to “16.0”, andtransmits transmission power information.

On the other hand, the base station 401 sets the transmission (power)level of PT-RS symbols (see FIG. 5A and FIG. 5B) in the PT-RStransmission regions for the user #1, i.e., the PT-RS transmissionregions 503 and 603 in carrier 4 and carrier 10 illustrated in FIG. 7and FIG. 8 to “2.0”, sets the transmission (power) level of PT-RSsymbols (see FIG. 5A and FIG. 5B) in the PT-RS transmission regions forthe user #2, i.e., the PT-RS transmission regions 503 and 603 in carrier16 and carrier 21 illustrated in FIG. 7 and FIG. 8 to “4.0”, and setsthe transmission (power) level of PT-RS symbols (see FIG. 5A and FIG.5B) in the PT-RS transmission regions for the user #3, i.e., the PT-RStransmission regions 503 and 603 in carrier 28 and carrier 33illustrated in FIG. 7 and FIG. 8 to “8.0”, and transmits transmissionpower information.

That is to say, the base station 401 differentiates the transmission(power) level control method for “symbols” (may be data symbols) intransmission regions excluding the PT-RS transmission region, and thetransmission (power) level control method for PT-RS symbols in the PT-RStransmission region, even for the same user. Alternatively, the basestation 401 differentiates the transmission (power) level control methodfor in transmission regions excluding the PT-RS transmission region, andthe transmission (power) level control method in the PT-RS transmissionregion, even for the same user.

At this time, the base station 401 controls the transmission power(power) level for “symbols” or “transmission regions” in transmissionregions excluding the PT-RS transmission region, such that securing datareception quality is achieved at terminals that are communicationpartners of the base station 401. On the other hand, the base station401 controls the transmission (power) level for PT-RS symbols in thePT-RS transmission region or for the PT-RS transmission region, suchthat a desired terminal can estimate phase noise with high precision,and other terminals can use the PT-RS symbols for estimating phasenoise.

This point will be described below by way of specific examples.

FIG. 10 illustrates an example of signal point layout in the in-phaseI-orthogonal Q plane (I-Q plane) in BPSK (Binary Phase Shift Keying). Inthe case of BPSK, two signal points are placed in the I-Q plane. If thesignal points are expressed as (I2, Q2), then (a2×z, 0) and (−a2×z, 0)exist for (I2, Q2). Note that coefficient a2 can be expressed in thefollowing Expression (24).

[Math 24]a2=1.0  Expression (24)

Also, z is a real number that is greater than 0. At this time, theaverage transmission power is z².

FIG. 11 illustrates an example of signal point layout in the I-Q planein QPSK (Quadrature Phase Shift Keying). In the case of QPSK, foursignal points are placed in the I-Q plane. If the signal points areexpressed as (I4, Q4), then (a4×z, a4×z), (−a4×z, a4×z), (a4×z, −a4×z),and (−a4×z, −a4×z) exist for (I4, Q4). Note that coefficient a4 can beexpressed in the following Expression (25).

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 25} \right\rbrack & \; \\{{a\; 4} = \frac{1}{\sqrt{2}}} & {{Expression}\mspace{14mu}(25)}\end{matrix}$

Also, z is a real number that is greater than 0. At this time, theaverage transmission power is z². That is to say, by setting a4 as inExpression (25), the transmission level of BPSK and the transmissionlevel of QPSK become equal.

FIG. 12 illustrates an example of signal point layout in the I-Q planein 16QAM (16 Quadrature Amplitude Modulation). In the case of 16QAM, 16signal points are placed in the I-Q plane. If the signal points areexpressed as (164, Q16), then (a16×z×3, a16×z×3), (a16×z×3, a16×z×1),(a16×z×3, −a16×z×1), (a16×z×3, −a16×z×3), (a16×z×1, a16×z×3), (a16×z×1,a16×z×1), (a16×z×1, −a16×z×1), (a16×z×1, −a16×z×3), (−a16×z×1, a16×z×3),(−a16×z×1, a16×z×1), (−a16×z×1, −a16×z×1), (−a16×z×1, −a16×z×3),(−a16×z×3, a16×z×3), (−a16×z×3, a16×z×1), (−a16×z×3, −a16×z×1), and(−a16×z×3, −a16×z×3) exist for (I16, Q16). Note that coefficient a16 canbe expressed in the following Expression (26).

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 26} \right\rbrack & \; \\{{a\; 16} = \frac{1}{\sqrt{10}}} & {{Expression}\mspace{14mu}(26)}\end{matrix}$

Also, z is a real number that is greater than 0. At this time, theaverage transmission power is z². That is to say, by setting a16 as inExpression (26), the transmission level of BPSK and the transmissionlevel of QPSK and the transmission level of 16QAM become equal.

FIG. 13 illustrates an example of signal point layout in the I-Q planein 64QAM (64 Quadrature Amplitude Modulation). In the case of 64QAM, 64signal points are placed in the I-Q plane. If the signal points areexpressed as (I64, Q64), then (a64×z×7, a64×z×7), (a64×z×7, a64×z×5),(a64×z×7, a64×z×3), (a64×z×7, a64×z×1), (a64×z×7, −a64×z×1), (a64×z×7,−a64×z×3), (a64×z×7, −a64×z×5), (a64×z29×7, −a64×z×7), (a64×z×5,a64×z×7), (a64×z×5, a64×z×5), (a64×z×5, a64×z×3), (a64×z×5, a64×z×1),(a64×z×5, −a64×z×1), (a64×z×5, −a64×z×3), (a64×z×5, −a64×z×5), (a64×z×5,−a64×z×7), (a64×z×3, a64×z×7), (a64×z×3, a64×z×5), (a64×z×3, a64×z×3),(a64×z×3, a64×z×1), (a64×z×3, −a64×z×1), (a64×z×3, −a64×z×3), (a64×z×3,−a64×z×5), (a64×z×3, −a64×z×7), (a64×z×1, a64×z×7), (a64×z×1, a64×z×5),(a64×z×1, a64×z×3), (a64×z×1, a64×z×1), (a64×z×1, −a64×z×1), (a64×z×1,−a64×z×3), (a64×z×1, −a64×z×5), (a64×z×1, −a64×z×7), (−a64×z×1,a64×z×7), (−a64×z×1, a64×z×5), (−a64×z×1, a64×z×3), (−a64×z×1, a64×z×1),(−a64×z×1, −a64×z×1), (−a64×z×1, −a64×z×3), (−a64×z×1, −a64×z×5),(−a64×z×1, −a64×z×7), (−a64×z×3, a64×z×7), (−a64×z×3, a64×z×5),(−a64×z×3, a64×z×3), (−a64×z×3, a64×z×1), (−a64×z×3, −a64×z×1),(−a64×z×3, −a64×z×3), (−a64×z×3, −a64×z×5), (−a64×z×3, −a64×z×7),(−a64×z×5, a64×z×7), (−a64×z×5, a64×z×5), (−a64×z×5, a64×z×3),(−a64×z×5, a64×z×1), (−a64×z×5, −a64×z×1), (−a64×z×5, −a64×z×3),(−a64×z×5, −a64×z×5), (−a64×z×5, −a64×z×7), (−a64×z×7, a64×z×7),(−a64×z×7, a64×z×5), (−a64×z×7, a64×z×3), (−a64×z×7, a64×z×1),(−a64×z×7, −a64×z×1), (−a64×z×7, −a64×z×3), (−a64×z×7, −a64×z×5), and(−a64×z×7, −a64×z×7) exist for (I64, Q64). Note that coefficient a64 canbe expressed in the following Expression (27).

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 27} \right\rbrack & \; \\{{a\; 64} = \frac{1}{\sqrt{42}}} & {{Expression}\mspace{14mu}(27)}\end{matrix}$

Also, z is a real number that is greater than 0. At this time, theaverage transmission power is z². That is to say, by setting a64 as inExpression (27), the transmission level of BPSK and the transmissionlevel of QPSK and the transmission level of 16QAM and the transmissionlevel of 64QAM become equal.

Now, a case of carrying out the following modulation scheme andtransmission level adjustment, in a case where the frame configurationof modulated signals transmitted by the base station 401 is the frameconfiguration illustrated in FIG. 7 and FIG. 8 will be described here asone example.

For example, the modulation scheme for the data symbols in the datatransmission regions 502 and 602 for the user #1 is QPSK, and theadjustment coefficient for the transmission level is b1. Note that thisb2 is equivalent to the post-change level α1 of the transmission leveldescribed above. In this case, the in-phase component ID1 of the datasymbols in the data transmission regions 502 and 602 after transmissionlevel adjustment is expressed by ID1=b1×I4, and the orthogonal componentQD1 of the data symbols of the data transmission regions 502 and 602after transmission level adjustment is expressed by QD1=b1×Q4.

Also, the modulation scheme for the data symbols in the datatransmission regions 502 and 602 for the user #2 is 16QAM, and theadjustment coefficient for the transmission level is b2. Note that thisb2 is equivalent to the post-change level a2 of the transmission leveldescribed above. In this case, the in-phase component ID2 of the datasymbols in the data transmission regions 502 and 602 after transmissionlevel adjustment is expressed by ID2=b2×I16, and the orthogonalcomponent QD2 of the data symbols of the data transmission regions 502and 602 after transmission level adjustment is expressed by QD2=b2×Q16.

Also, for example, the modulation scheme for the data symbols in thedata transmission regions 502 and 602 for the user #3 is 64QAM, and theadjustment coefficient for the transmission level is b3. In this case,the in-phase component ID3 of the data symbols in the data transmissionregions 502 and 602 after transmission level adjustment is expressed byID3=b3×I64, and the orthogonal component QD3 of the data symbols of thedata transmission regions 502 and 602 after transmission leveladjustment is expressed by QD3=b3×Q64.

On the other hand, the modulation scheme for the PT-RS symbols in thePT-RS transmission regions 503 and 603 for the user #1 is BPSK, and theadjustment coefficient for the transmission level is c1, for example.Note that this c1 is equivalent to the post-change value β1 of thetransmission level described above. In this case, the in-phase componentIP1 of the PT-RS symbols in the PT-RS transmission region 503 and 603after transmission level adjustment is expressed by IP1=c1×I2, and theorthogonal component QP1 of the PT-RS symbols of the PT-RS transmissionregions 503 and 603 after transmission level adjustment is expressed byQP1=c1×Q2.

Also, the modulation scheme for the PT-RS symbols in the PT-RStransmission regions 503 and 603 for the user #2 is BPSK, and theadjustment coefficient for the transmission level is c2, for example.Note that this c2 is equivalent to the post-change value β2 of thetransmission level described above. In this case, the in-phase componentIP2 of the PT-RS symbols in the PT-RS transmission region 503 and 603after transmission level adjustment is expressed by IP2=c2×I2, and theorthogonal component QP2 of the PT-RS symbols of the PT-RS transmissionregions 503 and 603 after transmission level adjustment is expressed byQP2=c2×Q2.

Also, the modulation scheme for the PT-RS symbols in the PT-RStransmission regions 503 and 603 for the user #3 is BPSK, and theadjustment coefficient for the transmission level is c3, for example. Inthis case, the in-phase component IP3 of the PT-RS symbols in the PT-RStransmission region 503 and 603 after transmission level adjustment isexpressed by IP3=c3×I2, and the orthogonal component QP3 of the PT-RSsymbols of the PT-RS transmission regions 503 and 603 after transmissionlevel adjustment is expressed by QP3=c3×Q2.

When performing the above transmission level adjustment, the basestation 401 can make the following settings (conditions).

“set b1 and c1 where b1 c1”

“set b2 and c2 where b2 c2”

“set b3 and c3 where b3 c3”

Although a case where user #1 through user #3 exist is described in theabove example, the number of users is not restricted to three, and thiscan be carried out in the same way with n users (where n is an integerof 2 or greater). That is to say, the base station 401 can set bk and ckwhere bk≠ck (where k is an integer of 1 or greater but n or smaller).

Also, when performing the above transmission level adjustment, the basestation 401 can make the following settings (conditions).

“time exists where one of b1≠c1, b2≠c2, and b3≠c3 hold”

Also, when the number of users is n, the following holds.

time exists where “k exists where bk≠ck, where k is an integer of 1 orgreater but n or smaller”

Also, the modulation scheme (mapping method) of the PT-RS symbols in thePT-RS transmission regions is described as being BPSK in the aboveexample, but this may be other modulation schemes. Also, BPSK, π/2-shiftBPSK, QPSK, π/4-shift QPSK, PAM (Pulse Amplitude Modulation) and soforth enable phase estimation, and accordingly are suitable methods forthe modulation scheme (mapping method) of the PT-RS symbols in the PT-RStransmission regions. Note however, that the mapping method is notrestricted to these methods, and operations the same as those describedabove can be carried out even with mapping where the averagetransmission power z² for the PT-RS symbols in the PT-RS transmissionregions before transmission level adjustment is not realized. Althoughthe symbols are multiplied by the adjustment coefficients b1, b2, c1,and c2 in the above example, this is not restrictive, adjustmentcoefficients may be multiplied as in any of Expression (1) throughExpression (21).

Also, the modulation scheme (mapping method) of the data symbols in thedata transmission regions is not restricted to BPSK, QPSK, 16QAM, and64QAM. For example, a non-uniform mapping method may be used as themapping method of the data symbols in the data transmission regions, orπ/2-shift BPSK or π/4-shift QPSK may be used. Note however, thatcoefficients corresponding to the above-described coefficients a2, a4,a16, and a64 need to be separately decided for each modulation scheme.

[Relation Between Transmission Level Adjustment Coefficients for DataSymbols and Transmission Level Adjustment Coefficients for PT-RSSymbols]

Next, the relation between transmission level adjustment coefficientsfor data symbols in the data transmission region and transmission leveladjustment coefficients for PT-RS symbols in the PT-RS transmissionregion will be described.

The minimum value of transmission level adjustment coefficients for datasymbols in the data transmission region is bmin, and the maximum valueis bmax. Note that bmin is a real number greater than zero, bmax is areal number, and bmin<bmax holds.

The transmission level adjustment coefficients b1, b2, and b3 (bk in acase where the number of terminals is n (where k is an integer of 1 orgreater but n or smaller)) described above is set to an appropriatevalue that is bmin or greater but bmax or smaller.

The minimum value of transmission level adjustment coefficients forPT-TS symbols in the PT-RS transmission region is cmin, and the maximumvalue is cmax. Note that cmin is a real number greater than zero, cmaxis a real number, and cmin<cmax holds.

The transmission level adjustment coefficients c1, c2, and c3 (ck in acase where the number of terminals is n (where k is an integer of 1 orgreater but n or smaller)) described above is set to an appropriatevalue that is cmin or greater but cmax or smaller.

At this time, cmin>bmin may hold. This enables the reception level ofPT-RS symbols to be secured. Thus, the possibility of each terminalbeing able to estimate phase noise using PT-RS symbols in the PT-RStransmission regions for other terminals is increased, and thepossibility that reception quality of data will improve is increased.

[Estimation Method of Transmission Level Correction Coefficients forPT-RS Symbols]

Next, an example of the estimation method of the transmission levelcorrection coefficient β for PT-RS symbols at a terminal (receptionapparatus illustrated in FIG. 9) will be described in detail.

Specifically, in the present embodiment, the transmission (power) levelcorrection coefficient β for PT-RS symbols in the PT-RS transmissionregions is associated with the pattern of the sequence used as PT-RSlaid out in the PT-RS transmission regions. The base station 401(transmission apparatus) and the terminals (reception apparatuses) sharethe correlation between the correction coefficient β and the PT-RSpattern.

Accordingly, by identifying the pattern of PT-RS laid out in the PT-RStransmission regions, the terminals can identify the transmission levelcorrection coefficient β correlated with this PT-RS pattern, even ifthere is no explicit notification regarding the correction coefficient βfrom the base station 401.

That is to say, by transmitting the PT-RS, the base station 401 canimplicitly make notification of the correction coefficient β (i.e., thetransmission power information for PT-RS). Accordingly, the need for thebase station 401 to add information regarding PT-RS symbol transmissionlevel in the PT-RS transmission regions to the control informationtransmission regions 500 and 600, for example, can be done away with.

Also, by making the control method of transmission (power) level usingthe correction coefficient a in transmission regions excluding the PT-RStransmission regions, and the control method of transmission (power)level in the PT-RS transmission regions (correction coefficient β) usingthe correction coefficient β, to be different, the terminals canidentify information relating to the PT-RS transmission (power) level(correction coefficient β), without seeing information relating to thedata transmission regions of other terminals. Accordingly, the terminalcan estimate phase noise with high precision using the PT-RS directedtoward other terminals, in addition to PT-RS directed toward itself,while maintaining data protection of other terminals.

A specific method will be described below.

For example, assumption will be made that any one of a a plurality ofcount m of correction coefficients β_(n) (where n=an integer of 1 to m)for the transmission level with regard to PT-RS is being used.

In this case, patterns of sequences used as PT-RS (hereinafter referredto as PT-RS patterns) are respectively associated with and set to the mcorrection coefficients β. Now, the PT-RS patterns are mutuallyorthogonal. For example, the PT-RS patterns may be mutually orthogonalas modulated signals, or may be mutually orthogonal as bit sequences ina case of using BPSK, QPSK, or the like.

Specifically, m types of PT-RS patterns are prepared, for example. Atthis time, the m types of PT-RS patterns is expressed as u_(n)(k). Thereare m types of PT-RS patterns that exist, so n is an integer of 1 orgreater but m or smaller (where m is an integer of two or greater). Atthis time, u_(n)(k) may be defined as a complex number, or may bedefined as a real number. Also, k is an integer of 0 or greater, as oneexample. Also, u_(n)(k) is a sequence of a cycle T (where T is aninteger of 2 or greater) (i.e., u_(n)(k=i)=u_(n)(k=i+T) holds). At thistime, in a case where PT-RS patterns (u_(n)(0) through u_(n)(T−1)) aremutually orthogonal as modulated signals, the following Expression (28)holds where x is an integer of 1 or greater but m or smaller, y is aninteger of 1 or greater but m or smaller, and x≠y holds.

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 28} \right\rbrack & \; \\{{\sum\limits_{k = 0}^{T - 1}{{u_{x}(k)} \times {u_{y}(k)}}} = 0} & {{Expression}\mspace{14mu}(28)}\end{matrix}$

Alternatively, m types of PT-RS patterns are prepared. At this time, them types of PT-RS patterns are expressed as bit sequence b_(n)(k) made upof {0, 1}. There are m types of PT-RS patterns that exist, so n is aninteger of 1 or greater but m or smaller (where m is an integer of twoor greater). At this time, k is an integer of 0 or greater, as oneexample. Also, b_(n)(k) is a bit sequence of a cycle T (where T is aninteger of 2 or greater) (i.e., b_(n)(k=i)=b_(n)(k=i+T) holds). At thistime, in a case where PT-RS patterns (b_(n)(0) through b_(n)(T−1)) aremutually orthogonal as bit sequences, the following Expression (29)holds where x is an integer of 1 or greater but m or smaller, y is aninteger of 1 or greater but m or smaller, and x≠y holds.

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 29} \right\rbrack & \; \\{{\sum\limits_{k = 0}^{T - 1}\left( {\left( {{2 \times {b_{x}(k)}} - 1} \right) \times \left( {{2 \times {b_{y}(k)}} - 1} \right)} \right)} = 0} & {{Expression}\mspace{14mu}(29)}\end{matrix}$

As one example, PT-RS patterns where the cycle of modulated signals inBPSK (i.e., in-phase I component is 1 or −1, and orthogonal component is0 (zero)) T=4, and m=4, will be described.

For example, an m=4 count of PT-RS patterns u₁ through u₄ are expressedas below so as to satisfy the relation in Expression (28).

PT-RS pattern u₁ is as follows.

u₁(0+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

u₁ (1+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

u₁ (2+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

u₁(3+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

where z is an integer or 0 or greater.

PT-RS pattern u₂ is as follows.

U₂(0+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

U₂(1+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

U₂(2+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

U₂(3+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

where z is an integer or 0 or greater.

PT-RS pattern u₃ is as follows.

U₃(0+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

U₃(1+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

U₃(2+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

U₃(3+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

where z is an integer or 0 or greater.

PT-RS pattern u₄ is as follows.

U₄(0+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

U₄(1+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

U₄(2+z×T)=(−1, 0) i.e., in-phase component −1, orthogonal component 0

U₄(3+z×T)=(1, 0) i.e., in-phase component 1, orthogonal component 0

where z is an integer or 0 or greater.

Also, the PT-RS patterns u₁ through u₄ are respectively correlated withcorrection coefficients β₁ through β₄ as follows.

When correction coefficient β₁=1.0 is set, the PT-RS pattern u₁ is used.

When correction coefficient β₁=2.0 is set, the PT-RS pattern u₂ is used.

When correction coefficient β₁=4.0 is set, the PT-RS pattern u₃ is used.

When correction coefficient β₁=8.0 is set, the PT-RS pattern u₄ is used.

First, the base station 401 (transmission apparatus) sets thetransmission (power) level correction coefficient β in the PT-RStransmission regions 503 and 603 within the transmission regions of eachuser. The base station 401 then uses the PT-RS pattern u associated withthe set correction coefficient β as the PT-RS symbol to be placed inthese PT-RS transmission regions 503 and 603.

That is to say, at the PT-RS transmission regions 503 and 603 within thetransmission regions for each user, a sequence (modulated signalsequence or but sequence) making up the PT-RS pattern associated withthe correction coefficient β set to these PT-RS transmission regions istransmitted. Note that the base station 401 sets the transmission levelcorrection coefficient β for each user transmission region, so the PT-RSpatterns transmitted at the transmission regions 503 and 603 within thetransmission regions for each user are each individually set.

On the other hand, the terminal (reception apparatus) identifies thecorrection coefficient β associated with the PT-RS received at the PT-RStransmission regions 503 and 603, based on the correlation between PT-RSpattern u and correction coefficient β.

Specifically, the terminal calculates a correlation value between thePT-RS received at each PT-RS transmission region 503 and 603 and thePT-RS patterns u₁ through u₄, and identifies a PT-RS pattern u_(n) wherethe correlation value is greatest. Note that the correlation value withregard to a PT-RS pattern u that is different from the PT-RS patternreceived in the PT-RS transmission region is zero, from the relationillustrated in Expression (28). The terminal then identifies thecorrection coefficient β_(n) associated with the PT-RS pattern u_(n)where the correlation value is greatest.

For example, in the above-described example, in a case where the PT-RSsymbol placed in the PT-RS transmission regions 503 and 603 within thetransmission region directed toward itself is the PT-RS pattern u₁, theterminal determines that the correction coefficient β₁=2.0 with regardto this PT-RS symbol. In the same way, the terminal identifies the PT-RSpattern u of the PT-RS symbol placed in the PT-RS transmission regions503 and 603 within the transmission region, and determines thecorrection coefficient β.

Thus, the terminals can each identify the correction coefficient β attransmission regions for other users, in addition to the correctioncoefficient β in the transmission region for itself. Accordingly, theterminal can estimate phase noise using PT-RS directed toward otheruser, in addition to its own PT-RS, by correcting the measurement valueof the PT-RS received at each user transmission region based on theidentified correction coefficient β.

Note that the example of the PT-RS pattern u_(n)(k) is not restricted tothe above-described example. Also, the PT-RS pattern u_(n)(k) may begenerated from b_(n)(k).

Thus, according to the present embodiment, the base station(transmission apparatus in FIG. 3) generates modulated signals wherePT-RS (reference signals for phase noise estimation) for a plurality ofreception apparatuses are each placed in resources allocated to the aplurality of reception apparatuses, and transmits the modulated signals.The transmission power correction coefficient for the PT-RS is alsoassociated with the sequence pattern used for the PT-RS.

Accordingly, even in a case where transmission power control of aplurality of users differ, the terminal (reception apparatus) cancorrectly estimate phase noise using the PT-RS directed to each userbased on the transmission power control (correction coefficient 13) foreach user. Thus, according to the present embodiment, each terminal canimprove estimation precision of phase noise using the PT-RS directed toa plurality of users, and can improve data transmission efficiency.

Also, each terminal can identify the correction coefficient β of thePT-RS of other user transmission regions at each terminal by observingthe PT-RS pattern at the PT-RS transmission regions, regardless of thedata symbols (transmission level correction coefficient a), i.e.,without observing the data symbols of the other users. Accordingly, dataprotection of other users can be realized at the time of a terminalperforming phase noise estimation.

Also, the correction coefficient β for the PT-RS transmission level isassociated with a PT-RS pattern being transmitted and implicitlynotified to the terminal. This can suppress increase in controlinformation for the correction coefficient.

(First Modification)

Although description has been made regarding the relation between PT-RSsymbols in PT-RS transmission regions and data symbols in datatransmission regions, with regard to transmission level adjustment, inthe embodiment above, this is not restrictive. For example, the PT-RStransmission region data symbols can be replaced with DM-RS symbols inthe DM-RS transmission regions. That is to say, transmission leveladjustment the same as in the above embodiment may be performedregarding PT-RS symbols in PT-RS transmission regions and DM-RS symbolsin DM-RS transmission regions.

(Second Modification)

A case has been described in the frame configuration illustrated in FIG.7 and FIG. 8 where PT-RS transmission regions (PT-RS symbols) are placed(inserted) for each user in the above-described embodiment. However, aframe configuration may be made where PT-RS transmission regions (PT-RSsymbols) are not placed, depending on the user. Also, frames forplacement of PT-RS transmission regions (PT-RS symbols) may be changed,and the frequency of insertion of PT-RS transmission regions (PT-RSsymbols) in resources in the frame, the number inserted, rules ofinsertion, insertion method, and so forth, may be changed.

For example, the base station 401 (transmission apparatus) may decidewhether or not to place PT-RS transmission regions (PT-RS symbols) inresources allocated to the terminals in accordance with the modulationscheme (i.e., modulation order) set for the signals of each terminal(user).

Also, the base station 401 (transmission apparatus) may change the framefor placement of the PT-RS transmission regions (PT-RS symbols) inresources allocated to the terminal in accordance with the modulationscheme (i.e., modulation order) set for signals of each terminal (user),and may change the frequency of insertion of PT-RS transmission regions(PT-RS symbols) in resources in the frame, the number inserted, rules ofinsertion, insertion method, and so forth. For example, the base station401 maps PT-RS transmission regions (PT-RS symbols) to resourcesallocated to the terminal in a case where the modulation order set tosignals for the terminal is a threshold value (e.g., the threshold valueis set to 16) or higher, and does not place PT-RS transmission regions(PT-RS symbols) in resources allocated to the terminal in a case wherethe modulation order is smaller than the threshold value. For example,the base station 401 transmits modulated signals directed to a certainterminal using 16QAM. At this time, the base station 401 transmits PT-RStransmission regions (PT-RS symbols). On the other hand, the basestation 401 transmits modulated signals by QPSK to a certain terminal.At this time, the base station 401 does not transmit PT-RS transmissionregions (PT-RS symbols). Note that the threshold value is not restrictedto 16, and may be another value.

Specifically, an arrangement may be made as explained below. When themodulation scheme for data symbols to the terminal has few modulationorders, such as BPSK (or π/2-shift BPSK) or QPSK (or π/4-shift QPSK),the base station 401 does not allocate PT-RS transmission regions (PT-RSsymbols) for this terminal. And the base station 401 allocates PT-RStransmission regions (PT-RS symbols) when there is a great number ofmodulation orders.

Another example will be described with reference to FIG. 14 and FIG. 15.For example, the base station 401 transmits a modulated signal to acertain terminal (e.g., user #2) by 16 QAM. At this time, for example,PT-RS transmission regions (PT-RS symbols) are transmitted using twocarriers out of the twelve carriers that are the transmission region forthe user #2, as illustrated in FIG. 14 and FIG. 15. Also, the basestation 401 transmits a modulated signal to a certain terminal (e.g.,user #1) by QPSK. At this time, PT-RS transmission regions (PT-RSsymbols) are transmitted by the base station 401 using just one carrierout of the twelve carriers that are the transmission region for the user#1 (when using carrier 1 through carrier 12, PT-RS transmission regions(PT-RS symbols) are placed only in carrier 4), as illustrated in FIG. 14and FIG. 15. Also, the base station 401 transmits a modulated signal toa certain terminal (e.g., user #3) by BPSK. At this time, PT-RStransmission regions (PT-RS symbols) are not placed by the base station401 in the twelve carriers that are in FIG. 14 and FIG. 15 (e.g., whencarrier 25 through carrier 36 are used, PT-RS transmission regions(PT-RS symbols) do not exist in carrier 25 through carrier 36).

Note that while the number of PT-RS transmission regions (PT-RS symbols)present in twelve carriers is changed according to the modulation schemein this example, methods of changing the frequency of insertion of PT-RStransmission regions (PT-RS symbols) is not restricted to this. Forexample, an example is illustrated in FIG. 7 and FIG. 8 where there iscontinuous placement of PT-RS transmission regions (PT-RS symbols) withregard to the temporal axis, the frequency of insertion of PT-TStransmission regions (PT-RS symbols) may be temporally switched.

For example, an arrangement may be made where, as illustrated in FIG. 16and FIG. 17, PT-RS transmission regions (PT-RS symbols) are temporallycontinuously placed in a case where the modulation scheme of a modulatedsignal to be transmitted to a certain terminal (e.g., user #1) is 16QAM,a PT-RS transmission region (PT-RS symbol) is placed every two symbolsbased on time in a case where the modulation scheme of a modulatedsignal to be transmitted to a certain terminal (e.g., user #2) is QPSK,and a PT-RS transmission region (PT-RS symbol) is placed every fivesymbols based on time in a case where the modulation scheme of amodulated signal to be transmitted to a certain terminal (e.g., user #3)is BPSK. Also, an arrangement may be made where the frequency ofinsertion of PT-RS transmission regions (PT-RS symbols) is switchedbased on time and based on frequencies depending on the modulationscheme. Also, an arrangement may be made where the rules of insertion ofPT-RS transmission regions (PT-RS symbols) is switched depending on themodulation scheme. Note that insertion rules may include a case of notinserting PT-RS transmission regions (PT-RS symbols).

Generally, the greater the number of modulation orders, the greater theinfluence of phase noise is. That is to say, when there is a greatnumber of modulation orders, the influence of deterioration in receptionperformance due to phase noise at the terminal can be reduced by placingPT-RS transmission regions (PT-RS symbols). On the other hand, when thenumber of modulation orders is small, the influence of phase noise issmall, so the influence of deterioration in reception performance due tophase noise is small even if there is no placement of PT-RS transmissionregions (PT-RS symbols) or the insertion frequency of PT-RS transmissionregions (PT-RS symbols) is low, and also this non-insertion or reductionof PT-RS transmission regions (PT-RS symbols) increases the datatransmission regions (data symbols), so data transmission efficiency canbe improved.

For example, in a communication system such as LTE (Long Term Evolution)or the like, the base station 401 transmits to a user (terminal)information of a MCS (Modulation and Coding Scheme) used by modulatedsignals that the base station 401 transmits. At this time, the basestation 401 may read the modulation order (or modulation scheme)indicated in the MCS for the user (based on the modulation order (ormodulation scheme) indicated in the MCS for the user) and decide whetheror not to place (insert) PT-RS transmission regions (PT-RS symbols) forthis user, or decide the insertion frequency or insertion rules of PT-RStransmission regions (PT-RS symbols) in the frame with regard to thisuser. In detail, the base station 401 decides not the MCS (i.e.,combination of modulation order (or modulation scheme) and codingefficiency (transmission speed)) itself, but rather whether or not toinclude PT-RS transmission regions (PT-RS symbols) based on themodulation order (or modulation scheme) included in the MCS.Alternatively, the base station 401 decides not the MCS (i.e.,combination of modulation order (or modulation scheme) and codingefficiency (transmission speed)) itself, but rather the insertionfrequency or insertion rules of PT-RS transmission regions (PT-RSsymbols) in the frame based on the modulation order (or modulationscheme) included in the MCS, for example. Note that “the insertionfrequency or insertion rules in the frame” may include “case of notinserting PT-RS transmission regions (PT-RS symbols)”.

Also, an arrangement may be made where the situation described belowoccurs. For example, assuming that 64QAM (Quadrature AmplitudeModulation) and 64APSK (Amplitude Phase Shift Keying) are selectable asmodulation schemes for a modulated signal to be transmitted to a user(terminal) by the base station 401, the base station 401 decides theinsertion frequency or insertion rules of PT-RS transmission regions(PT-RS symbols) to the frame, in accordance with information of themodulation scheme included in the MCS, for example. At this time, theinsertion frequency (insertion rules) of PT-RS transmission regions(PT-RS symbols) to the frame in a case of the base station 401 havingselected 64QAM, and the insertion frequency (insertion rules) of PT-RStransmission regions (PT-RS symbols) to the frame in a case of havingselected 64APSK, may be different. Also, the insertion frequency(insertion rules) of PT-RS transmission regions (PT-RS symbols) to theframe in a case of the base station 401 having selected 64QAM, and theinsertion frequency (insertion rules) of PT-RS transmission regions(PT-RS symbols) to the frame in a case of having selected 64APSK, may bedifferent. Note that the insertion frequency or insertion rules mayinclude a case of not inserting PT-RS transmission regions (PT-RSsymbols).

Also, the base station 401 can select between (uniform) 64QAM and NU(Non-Uniform) 64QAM for the modulation scheme of a modulated signaltransmitted to the user (terminal). At this time, the base station 401decides the insertion frequency or insertion rules of PT-RS transmissionregions (PT-RS symbols) to the frame, in accordance with information ofthe modulation scheme included in the MCS, for example, in which theinsertion frequency (insertion rules) of PT-RS transmission regions(PT-RS symbols) to the frame in a case of the base station 401 havingselected 64QAM, and the insertion frequency (insertion rules) of PT-RStransmission regions (PT-RS symbols) to the frame in a case of havingselected NU-64QAM, may be different. Note that the insertion frequencyor insertion rules may include a case of not inserting PT-RStransmission regions (PT-RS symbols). The above is an example, and canbe expressed differently as follows. The base station 401 can selectbetween a first modulation scheme and a second modulation scheme havingN (wherein N is an integer of 2 or greater) signals in an in-phaseI—orthogonal Q plane for the modulation scheme of a modulated signaltransmitted to the user (terminal). Accordingly, the modulation orderfor the first modulation scheme is N, and the modulation order for thesecond modulation scheme is also N, but the signal point layout on thein-phase I-orthogonal Q plane in the first modulation scheme and thesignal point layout on the in-phase I—orthogonal Q plane in the secondmodulation scheme differ. At this time, the base station 401 decides theinsertion frequency or insertion rules of PT-RS transmission regions(PT-RS symbols) to the frame, in accordance with information of themodulation scheme included in the MCS, for example, in which theinsertion frequency (insertion rules) of PT-RS transmission regions(PT-RS symbols) to the frame in a case of the base station 401 havingselected the first modulation scheme, and the insertion frequency(insertion rules) of PT-RS transmission regions (PT-RS symbols) to theframe in a case of having selected the second modulation scheme, may bedifferent. Note that the insertion frequency or insertion rules mayinclude a case of not inserting PT-RS transmission regions (PT-RSsymbols).

For example, in a case where the transmission speed is fast inaccordance with the order of MCS indices, there are cases where an MCSindex with a smaller modulation order is greater than an MCS index witha greater modulation order, depending on the combination of modulationorder and coding efficiency in each MCS. Accordingly, if determinationis made regarding whether or not to place PT-RS transmission regions(PT-RS symbols) is made in accordance with the MCS (index), a situationcan occur where PT-RS transmission regions are placed with an MCS wherethe modulation order is great, and PT-RS transmission regions are notplaced with an MCS where the modulation order is small. Accordingly,determining whether or not to place PT-RS transmission regions dependingon the MCS may result in PT-RS transmission regions not being placed ina situation where there is need to improve the estimation precision ofphase noise, and reception performance of the terminal may deteriorate.

Conversely, in the second modification, the base station 401 canappropriately judge whether or not to use PT-RS transmission regions,the insertion frequency, and insertion rules, taking into considerationthe modulation order and/or signal point placement, or effects of phasenoise that may be dependent on the modulation scheme, by determiningwhether or not to place PT-RS transmission regions or deciding theinsertion frequency and insertion rules of PT-RS transmission regions,based on the modulation order included in the MCS and/or signal pointplacement. Accordingly, deterioration of reception performance at theterminal can be suppressed.

(Third Modification)

The base station 401 may switch whether or not to insert PT-RStransmission regions (PT-RS symbols), the frequency of insertion, andinsertion rules, based on feedback information from the terminal.

For example, the oscillator that may be the primary cause of phase noiseat conceivably is less expensive and lower in performance at theterminal as compared to the base station. Accordingly, there is a highpossibility that occurrence of phase noise will be due to the oscillatorof the terminal, rather than the oscillator of the base station.

Accordingly, the terminal may monitor the demodulation results of thedata, and give feedback of information indicating whether or not thereis a need to place PT-RS transmission regions (PT-RS symbols), thefrequency of insertion, and insertion rules to the base station 401. Thebase station 401 then allocates PT-RS transmission regions (PT-RSsymbols) to terminals where there is great influence of phase noise, andallocates no PT-RS transmission regions (PT-RS symbols) to terminalswhere there is little influence of phase noise. Alternatively, the basestation 401 densely inserts PT-RS transmission regions (PT-RS symbols)with regard to terminals where there is great influence of phase noise,and sparsely inserts PT-RS transmission regions (PT-RS symbols) withregard to terminals where there is little influence of phase noise.

Accordingly, phase noise can be estimated using PT-RS transmissionregions (PT-RS symbols) for terminals where there is great influence ofphase noise, and reduce the effects of phase noise. On the other hand,PT-RS transmission regions (PT-RS symbols) are not inserted or insertedwith a sparse frequency for terminals where there is little influence ofphase noise, so data transmission efficiency can be improved due to theincrease in PT-RS transmission regions (PT-RS symbols).

(Fourth Modification)

Precoding of DMRS, data, and PT-RS is set with regard to each terminal(reception apparatus). Accordingly, at the time of a certain terminalusing the PT-RS of another terminal to estimate phase noise as describedabove, the difference in precoding among the terminals is problematic.That is to say, in a case where precoding differs from another terminal,there is a problem that the terminal cannot use the PR-RS of the otherterminal as it is.

Accordingly, the PT-RS symbols for each terminal are made to be inadjacent frequency regions in a fourth modification to solve thisproblem.

FIG. 18 illustrates a modification of the frame configuration of amodulated signal 108_A in FIG. 7 described in the above embodiment, andFIG. 19 illustrates a modification of the frame configuration of amodulated signal 108_B in FIG. 8 described in the above embodiment.

The point where FIG. 18 and FIG. 19 differ from FIG. 7 and FIG. 8 isthat the PT-RS symbols for each user in the PT-RS transmission regions503 and 603 are placed at the highest frequency (carrier) and lowestfrequency (carrier) of the transmission region (resources) that eachuser uses. That is to say, the base station 401 allocates the PT-RStransmission regions (PT-RS symbols) at the highest frequency and thelowest frequency of the resources allocated to the terminal.

Accordingly, depending on user appropriation, the PT-RS transmissionregions 503 and 603 are placed in two consecutive carriers. For example,in FIG. 18 and FIG. 19, PT-RS symbols for different users are placed inadjacent frequencies (carriers), at (carrier 12 and carrier 13), and(carrier 24 and carrier 25).

Thus, when there are PT-RS transmission regions placed in consecutivecarriers, the terminal (reception apparatus) can easily performestimation of intercarrier interference (ICI: Inter-CarrierInterference). Note that at the time of a terminal estimating the ICIusing PT-RS transmission regions placed in consecutive carriers, theprecoding matrix used in the transmission region of the user #1, theprecoding matrix used in the transmission region of the user #2, and theprecoding matrix used in the transmission region of the user #3 may bethe same, or may be different.

Further, even in a case where the precoding matrix used in thetransmission region of the user #1, the precoding matrix used in thetransmission region of the user #2, and the precoding matrix used in thetransmission region of the user #3 are different, each terminal canestimate phase noise using DM-RS symbols in the DM-RS transmissionregions of other users.

For example, in FIG. 18 and FIG. 19, the terminal (reception apparatus)of the user #2 can estimate phase noise using the DM-RS transmissionregions in carrier 13 and carrier 24 within the transmission region ofthe user #2. Further, the terminal of the user #2 can estimate phasenoise using the DM-RS transmission region in carrier 12 within thetransmission region of the user #1 and the DM-RS transmission region incarrier 25 within the transmission region of the user #3, in order toestimate phase noise.

Now, the carrier 13 that is a transmission region of the user #2 and thecarrier 12 that is a transmission region of the user #1 are adjacent,and channel fluctuations of the carrier 13 and carrier 12 can be deemedto be almost equal. Accordingly, the terminal of the user #2 canestimate the precoding matrix used in the transmission region for theuser #1, using the DM-RS transmission region of the carrier 12 withinthe transmission region for the user #1 and the DM-RS transmissionregion of the carrier 13 within the transmission region for the user #2.

In detail, the reception signal level estimated at the terminal usingthe DM-RS transmission region is decided from channel characteristics ofthis DM-RS transmission region, and the precoding matrix used in thisDM-RS transmission region. Accordingly, the terminal of the user #2comprehends the precoding matrix used in the transmission region of theuser #2, and thus can estimate the channel fluctuation (channelcharacteristics) of the carrier 13 from the reception signal levelmeasured in the DM-RS transmission region in the carrier 13 within thetransmission region of the user #2. The estimated channelcharacteristics of the carrier 13 and the channel characteristics of thecarrier 12 can be deemed to be equal, so the terminal of the user #2 canestimate the precoding matrix used in the transmission region of theuser #1 from the reception signal level measured in the DM-RStransmission region of the carrier 12.

Thus, the terminal of the user #2 can estimate the phase noise using thePT-RS transmission region of the carrier 12 within the transmissionregion of the user #1, by estimating the precoding matrix used in thetransmission region of the user #1 by using the DM-RS transmissionregion of the carrier 12 that is a transmission region of the user #1.Accordingly, even in a case where the precoding used differs between theuser #2 and the user #1, the terminal of the user #2 can perform phaseestimation using the PT-RS of the user #1 in addition to the PT-RS ofthe user #2, and phase estimation precision can be improved.

Further, intercarrier interference can be easily estimated by theterminal, by using adjacent carriers as described above.

In the same way, the carrier 24 that is a transmission region of theuser #2 and the carrier 25 that is a transmission region of the user #3are adjacent, and channel fluctuations of the carrier 24 and carrier 25can be deemed to be almost equal. Accordingly, the terminal of the user#2 can estimate the precoding matrix used in the transmission region forthe user #3, using the DM-RS transmission region of the carrier 24within the transmission region for the user #2 and the DM-RStransmission region of the carrier 25 within the transmission region forthe user #3. Accordingly, even in a case where the precoding useddiffers between the user #2 and the user #3, the terminal of the user #2can perform phase estimation using the PT-RS of the user #3 in additionto the PT-RS of the user #2, and phase estimation precision can beimproved. Further, intercarrier interference can be easily estimated bythe terminal, by using adjacent carriers, as described above.

Note that the carriers where PT-RS transmission regions are placed arenot restricted to two carriers per user as illustrated in FIG. 7 andFIG. 8, and the same can be carried out if PT-RS transmission regionsare disposed with one carrier or more for each user. There may be caseswhere no PT-RS transmission region is disposed for a certain user.

(Fifth Modification)

In a fifth modification, the base station 401 (transmission apparatus)allocates PT-RS transmission regions in a resource region (resourceblock) where there is no user appropriation. Each terminal (receptionapparatus) that is a communication partner with the base station 401 canuse the PT-RS transmission regions that exist in the region with no userappropriation for phase noise estimation. Accordingly, each terminal canimprove the estimation precision for phase noise, and the receptionquality of data can be improved.

A first example through a fourth example will be described as an exampleof the frame configuration in the fifth modification.

First Example

FIG. 20 illustrates a modification of the frame configuration of themodulated signal 108_A in FIG. 7 described in the embodiment above, andFIG. 21 illustrates a modification of the frame configuration of themodulated signal 108_B in FIG. 8 described in the embodiment above.

FIG. 20 and FIG. 21 differ from FIG. 7 and FIG. 8 with regard to thepoint that there is an unused time-frequency region where no user datatransmission region has been allocated, and that the PT-RS transmissionregions 503 and 603 and DM-RS transmission regions 501 and 601 areplaced in the unused time-frequency region.

For example, the terminal (reception apparatus) of the user #2 uses thePT-RS transmission region directed toward the user #2, i.e., the PT-RStransmission regions 503 and 603 in the carrier 16 and carrier 21illustrated in FIG. 20 and FIG. 21, for phase noise estimation. Further,the terminal of the user #2 may use at least the PT-RS transmissionregion (DM-RS transmission region may be used) inserted to the unusedtime-frequency region, in addition to the PT-RS transmission regionsdirected toward itself, i.e., the PT-RS transmission regions 503 and 603in the carrier 28 and carrier 33 illustrated in FIG. 20 and FIG. 21 (theDM-RS transmission regions 501 and 601 may be used), for phase noiseestimation. Accordingly, the terminal of the user #2 can improve theestimation precision of phase noise, and can improve reception qualityof data.

The DM-RS transmission regions 501 and 601 are placed at time $1 in thecarrier 28 and carrier 33 illustrated in FIG. 20 and FIG. 21, in thesame way as in the transmission region for the user #1 and thetransmission region for the user #2. Thus, the terminal of the user #2(or user #1) can perform channel estimation using the DM-RS transmissionregions 501 and 601 in carrier 28 and carrier 33. Accordingly, theterminal of the user #2 (or user #1) can improve channel estimationprecision, and can improve reception quality of data.

Note that the carriers where PT-RS transmission regions are placed arenot restricted to two carriers per user as illustrated in FIG. 20 andFIG. 21, and the same can be carried out if PT-RS transmission regionsare disposed in one or more carriers for each user. There may be caseswhere no PT-RS transmission region is disposed for a certain user.

Also, the PT-RS transmission regions placed in the unused time-frequencyregion where there is no user appropriation are not restricted to twocarriers, and the same can be carried out if PT-RS transmission regionsare placed in one or more carriers. The configuration of the DM-RStransmission regions placed in the unused time-frequency region wherethere is no user appropriation is not restricted to that illustrated inFIG. 20 and FIG. 21, and two or more may be placed at time $1.

Note that in FIG. 20 and FIG. 21, DM-RS transmission regions are placedin carrier 28 and carrier 33 where PT-RS transmission regions areplaced. This is advantageous in that the terminals can easily use thePT-RS transmission regions for phase noise estimation.

For example, the precoding used at the transmission region for the user#1 and the precoding matrix used at the transmission region for the user#2 is the same, this precoding matrix being expressed as Fc.

At this time, using the precoding matrix Fc is one suitable method atthe PT-RS transmission regions (and DM-RS transmission regions) incarrier 28 and carrier 33 in FIG. 20 and FIG. 21. For example, there isthe advantage that the terminal of the user #2 can easily use the PT-RStransmission regions (and DM-RS transmission regions) in carrier 28 andcarrier 33 for estimation of phase noise, since the precoding matrixused in the transmission region transmitted to itself and the precodingmatrix used in carrier 28 and carrier 33 are the same.

As another suitable method, precoding is not performed, or a precodingmatrix Fx is that in the following Expressions (30) or (31) in the PT-RStransmission regions (and DM-RS transmission regions) in carrier 28 andcarrier 33 in FIG. 20 and FIG. 21.

$\begin{matrix}\left\lbrack {{Math}\mspace{14mu} 30} \right\rbrack & \; \\{{Fx} = \begin{pmatrix}1 & 0 \\0 & 1\end{pmatrix}} & {{Expression}\mspace{14mu}(30)} \\{{Alternatively},} & \; \\\left\lbrack {{Math}\mspace{14mu} 31} \right\rbrack & \; \\{{Fx} = \begin{pmatrix}c & 0 \\0 & c\end{pmatrix}} & {{Expression}\mspace{14mu}(31)}\end{matrix}$

Note that c is a real number other than 0.

Accordingly, there is the advantage that the terminal of the user #2 caneasily know the precoding matrix used at the carrier 28 and carrier 33,and can easily use the PT-RS transmission regions (and DM-RStransmission regions) in carrier 28 and carrier 33 for phase noiseestimation. The base station 401 (transmission apparatus) does not haveto perform complex arithmetic by precoding matrix in the carrier 28 andcarrier 33, yielding an advantage in that the amount of computation canbe reduced. Note however, that the precoding method (precoding matrixused) in the PT-RS transmission regions (and DM-RS transmission regions)in carrier 28 and carrier 33 in FIG. 20 and FIG. 21 is not restricted tothe above example.

Next, a case where a precoding matrix is set for each user will bedescribed with reference to FIG. 20 and FIG. 21. In this case,Expression (30) and Expression (31) can be listed as precoding matricessuitable for the PT-RS transmission regions (and DM-RS transmissionregions) placed in the unused time-frequency region where there is nouser appropriation in FIG. 20 and FIG. 21. Note however, that theprecoding method (precoding matrix to be used) in the PT-RS transmissionregions (and DM-RS transmission regions) is not restricted to the aboveexample.

Accordingly, there is the advantage that the terminal of the user #2 caneasily know the precoding matrix used at the carrier 28 and carrier 33,and can easily use the PT-RS transmission regions (and DM-RStransmission regions) in carrier 28 and carrier 33 for phase noiseestimation. The base station 401 does not have to perform complexarithmetic by precoding matrix in the carrier 28 and carrier 33,yielding an advantage in that the amount of computation can be reduced.

Note however, that the precoding method to be used in the PT-RStransmission regions (and DM-RS transmission regions) in carrier 28 andcarrier 33, for example, which is placed in the unused time-frequencyregion where there is no user appropriation, is not restricted to theabove example.

Second Embodiment

FIG. 22 illustrates a modification of the frame configuration of themodulated signal 108_A in FIG. 7 described in the embodiment above, andFIG. 23 illustrates a modification of the frame configuration of themodulated signal 108_B in FIG. 8 described in the embodiment above.

FIG. 22 and FIG. 23 differ from FIG. 7 and FIG. 8 with regard to thepoint that there is an unused time-frequency region where no user datatransmission region has been allocated, and that the PT-RS transmissionregions 503 and 603, and DM-RS transmission regions 501 and 601, areplaced in the unused time-frequency region, in the same way as in thefirst example (FIG. 20 and FIG. 21).

In FIG. 22 and FIG. 23, the PT-RS transmission regions (and DM-RStransmission regions) are placed at the lowest frequency and the highestfrequency of the user transmission regions or unused region, and thePT-RS symbol are in adjacent frequency regions, as in the fourthmodification (FIG. 18 and FIG. 19).

Accordingly, the phase estimation precision can be improved, andfurther, intercarrier interference can be readily estimated, in the sameway as with the fourth modification.

The configuration method of PT-RS transmission regions and DM-RStransmission regions placed in the unused time-frequency region wherethere is no user appropriation, the configuration method of precodingmatrices used on each transmission region, and advantages thereof, arethe same as described in the first example, so description will beomitted.

Third Example

FIG. 24 illustrates a modification of the frame configuration of themodulated signal 108_A in FIG. 7 described in the embodiment above, andFIG. 25 illustrates a modification of the frame configuration of themodulated signal 108_B in FIG. 8 described in the embodiment above.

In FIG. 24 and FIG. 25, there is an unused time-frequency region whereno user data transmission region has been allocated, and the PT-RStransmission regions 503 and 603 are placed in the unused time-frequencyregion, in the same way as in the first example (FIG. 20 and FIG. 21). Acharacteristic point in FIG. 24 and FIG. 25 is that PT-RS transmissionregions are placed in the unused time-frequency region where there is nouser appropriation, at time $1 where the DM-RS transmission regions 501and 601 are placed in the transmission region of the user #1 and thetransmission region of the user #2.

For example, the terminal of the user #2 uses the PT-RS transmissionregions for the user #2, i.e., the PT-RS transmission regions 503 and603 in carrier 16 and carrier 21 illustrated in FIG. 24 and FIG. 25, forphase noise estimation. Further, the terminal of the user #2 may use atleast the PT-RS transmission regions inserted into the unusedtime-frequency region, i.e., the PT-RS transmission regions 503 and 603in the carrier 28 and carrier 33 illustrated in FIG. 24 and FIG. 25, forphase noise estimation, in addition to the PT-RS transmission region foritself. Accordingly, the terminal of the user #2 can improve estimationprecision of phase noise, and improve reception quality of data.

Also, by the PT-RS transmission regions 503 and 603 being placed at time$1 in the carrier 28 and carrier 33 illustrated in FIG. 24 and FIG. 25,the terminal of the user #2 (and user #1) can perform channel estimationand/or phase noise estimation, using the PT-RS transmission regions incarrier 28 and carrier 33. Accordingly, the estimation precision ofdistortion (e.g., channel fluctuation, effects of phase noise) can beimproved, and reception quality of data can be improved.

Also, no DM-RS transmission region is provided at time $1 in the carrier28 and carrier 33 illustrated in FIG. 24 and FIG. 25, so the terminal ofuser #2 (and user #1) does not have to give thought to a precodingmatrix for DM-RS transmission region. That is to say, the terminal ofuser #2 (and user #1) only needs to give consideration to precodingmatrices for PT-RS transmission regions. Accordingly, this isadvantageous in that estimation of distortion (e.g., channelfluctuation, effects of phase noise) can be simplified.

Note that the carriers where PT-RS transmission regions are placed arenot restricted to two carriers per user as illustrated in FIG. 24 andFIG. 25, and the same can be carried out if PT-RS transmission regionsare disposed in one or more carriers for each user. There may be caseswhere no PT-RS transmission region is disposed for a certain user.

Also, the PT-RS transmission regions placed in the unused time-frequencyregion where there is no user appropriation are not restricted to twocarriers, and the same can be carried out if PT-RS transmission regionsare placed in one or more carriers.

Here, for example, the precoding used at the transmission region for theuser #1 and the precoding matrix used at the transmission region for theuser #2 is the same, and this precoding matrix is expressed as Fc.

At this time, using the precoding matrix Fc is one suitable method atthe PT-RS transmission regions in carrier 28 and carrier 33 in FIG. 24and FIG. 25. For example, there is the advantage that the terminal ofthe user #2 can easily use the PT-RS transmission regions in carrier 28and carrier 33 for estimation of phase noise, since the precoding matrixused in the transmission region transmitted to itself and the precodingmatrix used in carrier 28 and carrier 33 are the same.

As another suitable method, precoding is not performed, or the precodingmatrix Fx is that in the following Expressions (30) or (31) in the PT-RStransmission regions in carrier 28 and carrier 33 in FIG. 24 and FIG.25.

Accordingly, there is the advantage that the terminal of the user #2 caneasily know the precoding matrix used at the carrier 28 and carrier 33,and can easily use the PT-RS transmission regions in carrier 28 andcarrier 33 for phase noise estimation (and channel estimation), forexample. The base station 401 does not have to perform complexarithmetic by precoding matrix in the carrier 28 and carrier 33,yielding the advantage in that the amount of computation can be reduced.

Next, a case where a precoding matrix is set for each user will bedescribed with reference to FIG. 24 and FIG. 25. In this case,Expression (30) and Expression (31) can be listed as precoding matricessuitable for the PT-RS transmission regions placed in the unusedtime-frequency region where there is no user appropriation in FIG. 24and FIG. 24.

Accordingly, there is the advantage that the terminal of the user #2 caneasily know the precoding matrix used at the carrier 28 and carrier 33,and can easily use the PT-RS transmission regions in carrier 28 andcarrier 33 for phase noise estimation (and channel estimation), forexample. The base station 401 does not have to perform complexarithmetic by precoding matrix in the carrier 28 and carrier 33,yielding an advantage in that the amount of computation can be reduced.

Note however, that the precoding matrix used in the PT-RS transmissionregions in carrier 28 and carrier 33 for example, placed in the unusedtime-frequency region where there is no user data appropriation, is notrestricted to the above example.

Fourth Example

FIG. 26 illustrates a modification of the frame configuration of themodulated signal 108_A in FIG. 7 described in the embodiment above, andFIG. 27 illustrates a modification of the frame configuration of themodulated signal 108_B in FIG. 8 described in the embodiment above.

In FIG. 26 and FIG. 27, there is an unused time-frequency region whereno user data transmission region has been allocated, and the PT-RStransmission regions 503 and 603 are placed in the unused time-frequencyregion, in the same way as in the third example (FIG. 24 and FIG. 25). Acharacteristic point in FIG. 26 and FIG. 27 is that PT-RS transmissionregions are placed in the unused time-frequency region where there is nouser data appropriation, at time $1 where the DM-RS transmission regions501 and 601 are placed in the transmission region of the user #1 and thetransmission region of the user #2 in the same way as in the thirdexample.

In FIG. 26 and FIG. 27, the PT-RS transmission regions (and DM-RStransmission regions) are placed at the lowest frequency and the highestfrequency of the user transmission regions or unused region, and thePT-RS symbol are in adjacent frequency regions, as in the fourthmodification (FIG. 18 and FIG. 19).

Accordingly, the phase estimation precision can be improved, andfurther, intercarrier interference can be readily estimated, in the sameway as with the fourth modification.

The configuration method of PT-RS transmission regions and DM-RStransmission regions placed in the unused time-frequency region wherethere is no user data appropriation, the configuration method ofprecoding matrices used on each transmission region, and advantagesthereof, are the same as described in the third example, so descriptionwill be omitted.

(Sixth Modification)

An arrangement may be made where one of the PT-RS symbols illustrated inFIG. 5A and the PT-RS symbols illustrated in FIG. 5B is a non-zero powersymbol. That is to say, one of the PT-RS symbols illustrated in FIG. 5Aand the PT-RS symbols illustrated in FIG. 5B does not exist (zeropower). Also, an arrangement may be made where PT-RS symbols exist inFIG. 5A, and PT-RS symbols do not exist in FIG. 5B.

Specifically, zero power is set in FIG. 5B at the same time-frequencyregion as the time-frequency region where the PT-RS symbols are placedin FIG. 5A (i.e., non-zero power). Alternatively, zero power is set inFIG. 5A at the same time-frequency region as the time-frequency regionwhere the PT-RS symbols are placed in FIG. 5B (i.e., non-zero power).

Also, PT-RS symbols and zero power symbols may exist in FIG. 5A and FIG.5B. For example, an arrangement is made where PT-RS symbols exist at thecarrier k, 4, and time $2 in FIG. 5A, zero power symbols exist at thecarrier k, 4, and time $3, PT-RS symbols exist at the carrier k, 4, andtime $4, zero power symbols exist at the carrier k, 4, and time $5, . .. ,. An arrangement is made where PT-RS symbols exist at the carrier k,10, and time $2 in FIG. 5A, zero power symbols exist at the carrier k,10, and time $3, PT-RS symbols exist at the carrier k, 10, and time $4,zero power symbols exist at the carrier k, 10, and time $5, . . . ,.

Also, an arrangement is made where zero symbols exist at the carrier k,4, and time 2 in FIG. 5B, PT-RS symbols exist at the carrier k, 4, andtime $3, zero power symbols exist at the carrier k, 4, and time $4,PT-RS symbols exist at the carrier k, 4, and time $5, . . . ,. Anarrangement is made where zero power symbols exist at the carrier k, 10,and time $2 in FIG. 5B, PT-RS symbols exist at the carrier k, 10, andtime $3, zero symbols exist at the carrier k, 10, and time $4, PT-RSsymbols exist at the carrier k, 10, and time $5, . . . ,.

It should be noted that the above two examples are only examples, andthe layout of PT-RS symbols and zero power symbols is not restricted tothis.

An arrangement may be made as a modified method of the above, where oneof the PT-RS transmission region illustrated in FIG. 7 and the PT-RSsymbols illustrated in FIG. 8 is non-zero power. That is to say, one ofthe PT-RS transmission region illustrated in FIG. 7 and the PT-RStransmission region illustrated in FIG. 8 does not exist (zero power).An arrangement may be made where a PT-RS transmission region exists inFIG. 7 and no PT-RS transmission region exists in FIG. 8.

Specifically, non-zero power is set in FIG. 8 at the same time-frequencyregion as the time-frequency region where the PT-RS transmission regionis placed in FIG. 7 (i.e., non-zero power). Alternatively, non-zeropower is set in FIG. 7 at the same time-frequency region as thetime-frequency region where the PT-RS transmission region is placed inFIG. 8 (i.e., non-zero power).

Also, PT-RS transmission regions and zero power symbols may exist inFIG. 7 and FIG. 8. For example, observing user #1, an arrangement ismade where a PT-RS transmission region exists at the carrier 4, and time$2 in FIG. 7, a zero power transmission region exists at the carrier 4,and time $3, a PT-RS transmission region exists at the carrier 4, andtime $4, a zero power transmission region exists at the carrier 4, andtime $5, . . . ,. An arrangement is made where a PT-RS transmissionregion exists at the carrier 10, and time $2 in FIG. 7, a zero powertransmission region exists at the carrier 10, and time $3, a PT-RStransmission region exists at the carrier 10, and time $4, a zero powertransmission region exists at the carrier 10, and time $5, . . . ,.

Also, an arrangement is made where a zero power transmission regionexists at the carrier 4, and time 2 in FIG. 8, a PT-RS transmissionregion exists at the carrier 4, and time $3, a zero power transmissionregion exists at the carrier 4, and time $4, a PT-RS transmission regionexists at the carrier 4, and time $5, . . . ,. An arrangement is madewhere a zero power transmission region exists at the carrier 10, andtime $2 in FIG. 8, a PT-RS transmission region exists at the carrier 10,and time $3, a zero power transmission region exists at the carrier 10,and time $4, a PT-RS transmission region exists at the carrier 10, andtime $5, . . . ,.

It should be noted that the above two examples are only examples, andthe layout of PT-RS transmission regions and zero power transmissionregions is not restricted to this.

The terminals can estimate the effects of phase noise in a modulatedsignal by the above configuration as well, and the embodiments of thepresent specification can be carried out.

(Seventh Modification)

Although MIMO transmission (where a plurality of streams are transmittedusing a plurality of antennas, for example) has been described in theabove embodiment, the transmission format is not restricted to MIMOtransmission.

For example, the base station 401 (transmission apparatus illustrated inFIG. 3) may apply a single-stream transmission method.

In this case, at the user #k modulated signal generator 104_killustrated in FIG. 4, for example, the post-mapping baseband signal206_1 (stream #X1) and post-mapping baseband signal 206_2 (stream #X2)that are the output of the mapping unit 205 are the same stream.

An example will be described regarding this point.

For example, the post-mapping baseband signal 206_1 and post-mappingbaseband signal 206_2 may be the same modulated signal.

As another example, in a case where the base station 401 is transmittinga first bit sequence by the post-mapping baseband signal 206_1, thefirst bit sequence is transmitted at the post-mapping baseband signal206_2 as well.

As another example, assumption will be made that a first symbol thattransmits a first bit sequence exists in the post-mapping basebandsignal 206_1. At this time, a symbol that transmits a first bit sequenceexists in the post-mapping baseband signal 206_2.

The baseband signals 206_1 and 206_2 that are the same stream may betransmitted from the antenna unit #A (111_A) and antenna unit #B (111_B)that are different, or the baseband signals 206_1 and 206_2 may betransmitted from a plurality of antennas.

Alternatively, an arrangement may be made where, at the user #kmodulated signal generator 104_k illustrated in FIG. 4, for example,only the baseband signal 206_1 (stream #X1) is output from the mappingunit 205, the modulated signal 208_A are output from the processing unit207, and the modulated signal 208_A are transmitted from one antennaunit #A (111_A). That is to say, single antenna transmission of a singlestream is executed by the mapping unit 205 and processing unit 207outputting a modulated signal corresponding to the configuration of oneantenna system (e.g., multiplexer 107, wireless unit 109, and antennaunit 111). Note that precoding is not performed at the processing unit207 at this time.

Alternatively, an arrangement may be made where, at the user #kmodulated signal generator 104_k illustrated in FIG. 4, for example,only the baseband signal 206_1 (stream #X1) is output from the mappingunit 205, modulated signals 208_A and 208_B subjected to signalprocessing at the processing unit 207 for CDD (Cyclic Delay Diversity)(or CSD: Cyclic Shift Diversity) are output, and the modulated signals208_A and 208_B are transmitted from the two of the antenna unit #A(111_A) and antenna unit #B (111_B), respectively. That is to say,multi-antenna transmission of a single stream is executed by outputtinga modulated signal corresponding to the configuration of two antennasystems (e.g., multiplexer 107, wireless unit 109, and antenna unit 111)with regard to one baseband signals output from the mapping unit 205.

Advantages the same as the examples described in the present embodimentcan be obtained with regard to a case where the base station transmitssingle-stream modulated signals, as described above. For example, anarrangement may be made where, single-stream modulated signals aregenerated of the frame configuration in FIG. 5A out of the frameconfigurations in FIG. 5A and FIG. 5B, and the description of thepresent embodiment above is carried out.

The base station also may transmit single-stream modulated signals ofthe frame configuration in FIG. 7. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 7 andFIG. 8 from the antennas. The method of generating the frameconfiguration in FIG. 7 and the frame configuration in FIG. 8 at thistime is as described above. The embodiment described above may becarried out using FIG. 7 and/or FIG. 8.

The base station also may transmit single-stream modulated signals ofthe frame configuration in FIG. 18. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 18and FIG. 19 from the antennas. The method of generating the frameconfiguration in FIG. 18 and the frame configuration in FIG. 19 at thistime is as described above. The embodiment described above may becarried out using FIG. 18 and/or FIG. 19.

The base station may transmit single-stream modulated signals of theframe configuration in FIG. 20. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 20and FIG. 21 from the antennas. The method of generating the frameconfiguration in FIG. 20 and the frame configuration in FIG. 21 at thistime is as described above. The embodiment described above may becarried out using FIG. 20 and/or FIG. 21.

The base station may transmit single-stream modulated signals of theframe configuration in FIG. 22. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 22and FIG. 23 from the antennas. The method of generating the frameconfiguration in FIG. 22 and the frame configuration in FIG. 23 at thistime is as described above. The embodiment described above may becarried out using FIG. 22 and/or FIG. 23.

The base station may transmit single-stream modulated signals of theframe configuration in FIG. 24. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 24and FIG. 25 from the antennas. The method of generating the frameconfiguration in FIG. 24 and the frame configuration in FIG. 25 at thistime is as described above. The embodiment described above may becarried out using FIG. 24 and/or FIG. 25.

The base station may transmit single-stream modulated signals of theframe configuration in FIG. 26. The base station may transmitsingle-stream modulated signals of the frame configuration in FIG. 26and FIG. 27 from the antennas. The method of generating the frameconfiguration in FIG. 26 and the frame configuration in FIG. 27 at thistime is as described above. The embodiment described above may becarried out using FIG. 26 and/or FIG. 27.

(Eighth Modification)

The base station 401 may transmit different data by post-mappingbaseband signal 206_1 (stream #X1) at symbol number i, and post-mappingbaseband signal 206_2 (stream #X2) at symbol number i, or may transmitthe same data.

For example, the base station 401 may transmit 1-bit data b0 in thepost-mapping baseband signal 206_1 (stream #X1) at symbol number i, andtransmit 1-bit data b0 in the post-mapping baseband signal 206_2 (stream#X2) at symbol number i.

Alternatively, the base station 401 may transmit 1-bit data b0 in thepost-mapping baseband signal 206_1 (stream #X1) at symbol number i, andtransmit 1-bit data b1 that is different from b0 in the post-mappingbaseband signal 206_2 (stream #X2) at symbol number i.

Accordingly, the base station 401 may set, for each user, “transmit aplurality of modulated signals of a plurality of streams” and “transmitmodulated signals of single stream”. Thus, “transmit a plurality ofmodulated signals of a plurality of streams” and “transmit modulatedsignals of single stream” may coexist in a frame.

In realizing the above, the base station (transmission apparatus in FIG.3) may have one or more error correction encoders 203, and may also haveone or more mapping units 205.

(Ninth Modification)

Although description has been made in the present embodiment regarding acase where, in MIMO transmission (transmitting a plurality of streamsusing, for example, a plurality of antennas), the base station forexample transmits PT-RS transmission regions (PT-RS symbols), DMRStransmission regions (DM-RS symbols), and data transmission regions(data symbols), in two modulated signals (two streams) from twoantennas, a configuration may be made where two modulated signals aretransmitted by one antenna, or three antennas. The terminal also cancarry out the present embodiment in a case of receiving modulatedsignals using one antenna, two antennas, or three antennas.

Although description has been made in the present embodiment regarding acase where, in MIMO transmission (transmitting a plurality of streamsusing, for example, a plurality of antennas), the base station forexample transmits PT-RS transmission regions (PT-RS symbols), DMRStransmission regions (DM-RS symbols), and data transmission regions(data symbols), in two modulated signals (two streams) from twoantennas, an arrangement may be made where, even in a case where thebase station transmits three or more modulated signals (three or morestreams) from a plurality of antennas, the present embodiment can becarried out in the same way by preparing three or more frameconfigurations described in the present embodiment, and the base stationgenerating and transmitting modulated signals. The terminal also cancarry out the present embodiment by receiving modulated signals usingone antenna, two antennas, or three antennas at this time.

Second Embodiment

In the present embodiment, PT-RS transmission in DFT-s-OFDM (DiscreteFourier Transform spread Orthogonal Frequency Division Multiplexing)transmission will be described.

[Configuration of Transmission Apparatus]

FIG. 28 is a block diagram illustrating a configuration example of atransmission apparatus according to the present embodiment. Thetransmission apparatus illustrated in FIG. 28 is a terminal or the like,for example.

In FIG. 28, an error correction encoder B104 takes data B101 and controlsignal B100 as input. The error correction encoder B104 subjects thedata B100 to error correction encoding based on information of the errorcorrection encoding format (e.g., error correction encoding method,error correction encoding block size, coding efficiency of errorcorrection encoding, etc.) included in the control signal B100, andgenerates and outputs post-error-correction-encoding data B105.

A modulated signal generator B106 takes thepost-error-correction-encoding data B105 and control signal B100 asinput. The modulated signal generator B106 performs mapping (modulation)on the post-error-correction-encoding data B105 based on information ofthe modulation scheme included in the control signal B100, and outputsstream #1 baseband signals B107_1 and stream #2 baseband signals B107_2.

A processing unit B108 takes as input the stream #1 baseband signalsB107_1, stream #2 baseband signals B107_2, DM-RS (B102), PT-RS (B103),and control signal B100. The processing unit B108 performs predeterminedprocessing (e.g., processing such as precoding, transmission powerchange, CDD (CSD), and so forth), based on information relating to theframe configuration, information relating to precoding, informationrelating to transmission power, information relating to CDD (CSD), andso forth, included in the control signal B100, and generates and outputsmodulated signal A (B109_A) and modulated signal B (B109_B).

Note that at the time of precoding processing, the processing unit B108may switch the precoding (matrix) used in the precoding processing inincrements of a plurality of symbols, or may perform precoding cyclingprocessing of switching the precoding (matrix) used in the precodingprocessing in increments of symbols.

A discrete Fourier transform unit B110_A takes the modulated signal A(B109_A) and control signal B100 as input. The discrete Fouriertransform unit B110_A subjects the modulated signal A (B109_A) todiscrete Fourier transform processing based on the control signal B100,and generates and outputs a post-discrete-Fourier-transform signal groupB111_A.

In the same way, a discrete Fourier transform unit B110_B takes themodulated signal B (B109_B) and control signal B100 as input. Thediscrete Fourier transform unit B110_B subjects the modulated signal B(B109_B) to discrete Fourier transform processing based on the controlsignal B100, and generates and outputs a post-discrete-Fourier-transformsignal group B111_B.

A subcarrier mapping unit B113_A takes as input thepost-discrete-Fourier-transform signal group B111_A, a zero signal groupB112_A, and control signal B100. The subcarrier mapping unit B113_A mapsthe post-discrete-Fourier-transform signal group B111_A and zero signalgroup B112_A to a subcarrier based on the control signals B100, andgenerates and outputs a post-subcarrier-mapping signal group B114_A.

In the same way, a subcarrier mapping unit B113_B takes as input thepost-discrete-Fourier-transform signal group B111_B, a zero signal groupB112_B, and control signal B100. The subcarrier mapping unit B113_B mapsthe post-discrete-Fourier-transform signal group B111_B and zero signalgroup B112_B to a subcarrier based on the control signal B100, andgenerates and outputs a post-subcarrier-mapping signal group B114_B.

An inverse (fast) Fourier transform unit (or inverse discrete Fouriertransform unit B115_A) takes the post-subcarrier-mapping signal groupB114_A and control signals B100 as input. The inverse (fast) Fouriertransform unit B115_A subjects the post-subcarrier-mapping signal groupB114_A to inverse (fast) Fourier transform (inverse discrete Fouriertransform) based on the control signal B100, and generates and outputspost-inverse-Fourier-transform signals B116_A.

In the same way, an inverse (fast) Fourier transform unit (or inversediscrete Fourier transform unit B115_B) takes thepost-subcarrier-mapping signal group B114_B and control signal B100 asinput. The inverse (fast) Fourier transform unit B115_B subjects thepost-subcarrier-mapping signal group B114_B to inverse (fast) Fouriertransform (inverse discrete Fourier transform) based on the controlsignal B100, and generates and outputs post-inverse-Fourier-transformsignals B116_B.

A cyclic prefix adding unit B117_A takes thepost-inverse-Fourier-transform signal B116_A and control signal B100 asinput. The cyclic prefix adding unit B117_A adds a cyclic prefix (CP:Cyclic Prefix) to the post-inverse-Fourier-transform signal B116_A basedon the control signal B100, and generates and outputspost-cyclic-prefix-adding signals B118_A.

In the same way, a cyclic prefix adding unit B117_B takes thepost-inverse-Fourier-transform signal B116_B and control signal B100 asinput. The cyclic prefix adding unit B117_B adds a cyclic prefix (CP) tothe post-inverse-Fourier-transform signals B116_B based on the controlsignal B100, and generates and outputs post-cyclic-prefix-adding signalsB118_B.

A wireless unit B119_A takes as input the post-cyclic-prefix-addingsignals B118_A and control signals B100. The wireless unit B119_Aperforms wireless-related processing on the post-cyclic-prefix-addingsignal B118_A based on the control signal B100, and generatestransmission signals A (B120_A). The transmission signals A (B120_A) areoutput from an antenna unit #A (B121_A) as radio waves.

In the same way, a wireless unit B119_B takes as input thepost-cyclic-prefix-adding signal B118_B and control signal B100. Thewireless unit B119_B performs wireless-related processing on thepost-cyclic-prefix-adding signals B118_B based on the control signalB100, and generates transmission signals B (B120_B). The transmissionsignal B (B120_B) are output from an antenna unit #B (B121_B) as radiowaves.

The antenna unit #A (B121_A) takes the control signal B100 as input. Theantenna unit #A (B121_A) may perform transmission directionality controlfollowing the control signal B100. Also, the control signal B100 doesnot have to exist as input of the antenna unit #A (B121_A). In the sameway, the antenna unit #B (B121_B) takes the control signal B100 asinput. The antenna unit #B (B121_B) may perform transmissiondirectionality control following the control signal B100. Also, thecontrol signal B100 does not have to exist as input of the antenna unit#B (B121_B).

[Frame Configuration of Stream]

FIG. 29(A) and FIG. 29(B) illustrate a frame configuration example ofthe stream #1 baseband signals B107_1 A and stream #2 baseband signalsB107_2 in FIG. 28. The horizontal axis is time in FIG. 29(A) and FIG.29(B).

Also in FIG. 29(A) and FIG. 29(B), “DFT-s-OFDM symbol” indicates a DFT(discrete Fourier transform) spread OFDM symbol. A DFT-s-OFDM symbol isconfigured of a data symbol, DM-RS symbol, or PT-RS symbol.

FIG. 29(A) illustrates an example of the frame configuration of stream#1. DFT-s-OFDM symbol B201_1_1 in FIG. 29(A) is a DFT-s-OFDM symbol ofstream #1 that the transmission apparatus (terminal) illustrated in FIG.28 transmits during a first time. DFT-s-OFDM symbol B201_1_2 is aDFT-s-OFDM symbol of stream #1 that the transmission apparatus transmitsduring a second time. DFT-s-OFDM symbol B201_1_3 is a DFT-s-OFDM symbolof stream #1 that the transmission apparatus transmits during a thirdtime.

One slot will be studied here. Accordingly, DFT-s-OFDM symbol B201_1_kis a DFT-s-OFDM symbol of stream #1 that the transmission apparatustransmits during a k′th time within one slot. For example, k is aninteger of 1 or greater but 7 or smaller.

The DFT-s-OFDM symbols B201_1_1, B201_1_2, B201_1_3, . . . , andB201_1_7, are configured of a data symbol of stream #1, DM-RS symbol ofstream #1, or PT-RS symbol of stream #2. At this time, the data symbolof stream #1 is equivalent to the stream #1 baseband signals B107_1 ofstream #1 in FIG. 28. Also, the DM-RS symbol of stream #1 and the PT-RSsymbol of stream #1 are equivalent to the DM-RS symbol of stream #1 andPT-RS symbol of stream #1 to be added to the stream #1 baseband signalsB107_1 (data symbol) of stream #1 in FIG. 28.

FIG. 29(B) illustrates an example of the frame configuration of stream#2. DFT-s-OFDM symbol B201_2_1 in FIG. 29(B) is a DFT-s-OFDM symbol ofstream #2 that the transmission apparatus (terminal) illustrated in FIG.28 transmits during a first time. DFT-s-OFDM symbol B201_2_2 is aDFT-s-OFDM symbol of stream #2 that the transmission apparatus transmitsduring a second time. DFT-s-OFDM symbol B201_2_3 is a DFT-s-OFDM symbolof stream #2 that the transmission apparatus transmits during a thirdtime.

One slot will be studied here. Accordingly, DFT-s-OFDM symbol B201_2_kis a DFT-s-OFDM symbol of stream #2 that the transmission apparatustransmits during a k′th time within one slot. For example, k is aninteger of 1 or greater but 7 or smaller.

The DFT-s-OFDM symbols B201_2_1, B201_2_2, B201_2_3, . . . , andB201_2_7, are configured of a data symbol of stream #2, DM-RS symbol ofstream #2, or PT-RS symbol of stream #2. At this time, the data symbolof stream #2 is equivalent to the stream #2 baseband signals B107_2 ofstream #2 in FIG. 28. Also, the DM-RS symbol of stream #2 and the PT-RSsymbol of stream #2 are equivalent to the DM-RS symbol of stream #2 andPT-TS symbol of stream #2 to be added to the stream #2 baseband signalsB107_2 (data symbol) of stream #2 in FIG. 28.

Note that the DM-RS (B102) in FIG. 28 includes the DM-RS symbol ofstream #1 and the DM-RS symbol of stream #2. Also, the PT-RS (B103) inFIG. 28 includes the PT-RS symbol of stream #1 and the PT-RS symbol ofstream #2.

Also, the DFT-s-OFDM symbol B201_1_1 in FIG. 29(A) and the DFT-s-OFDMsymbol B201_2_1 in FIG. 29(B) are transmitted from the transmissionapparatus using a plurality of antennas (antenna unit #A and antennaunit #B), using the same frequency during the first time (same time). Inthe same way, the DFT-s-OFDM symbol B201_1_2 in FIG. 29(A) and theDFT-s-OFDM symbol B201_2_2 in FIG. 29(B) are transmitted from thetransmission apparatus using a plurality of antennas (antenna unit #Aand antenna unit #B), using the same frequency during the second time(same time). Also, the DFT-s-OFDM symbol B201_1_3 in FIG. 29(A) and theDFT-s-OFDM symbol B201_2_3 in FIG. 29(B) are transmitted from thetransmission apparatus using a plurality of antennas (antenna unit #Aand antenna unit #B), using the same frequency during the third time(same time). Thereafter, in the same way, the DFT-s-OFDM symbol B201_1_7and the DFT-s-OFDM symbol B201_2_7 are transmitted (omitted fromillustration) from the transmission apparatus using a plurality ofantennas (antenna unit #A and antenna unit #B), using the same frequencyduring the seventh time (same time).

[Frame Configuration of a Modulated Signal]

FIG. 30(A) and FIG. 30(B) illustrate an example frame configuration ofthe modulated signal A (B109_A) and modulated signal B (B109_B). Thehorizontal axis in FIG. 30(A) and FIG. 30(B) is time.

In FIG. 30(A) and FIG. 30(B), “DFT-s-OFDM transmission region” is thetransmission region of DFT spread OFDM.

The DFT-s-OFDM transmission region in FIG. 30(A) shows the modulatedsignal A (B109_A) in FIG. 28, and the DFT-s-OFDM transmission region inFIG. 30(B) shows the modulated signal B (B109_B) in FIG. 28.

The DFT-s-OFDM transmission region B301_1_1 in FIG. 30(A) is signalsobtained by performing processing on the DFT-s-OFDM symbol B201_1_1 inFIG. 29(A) and the DFT-s-OFDM symbol B201_2_1 in FIG. 29(B) at theprocessing unit B108 in FIG. 28. The DFT-s-OFDM transmission regionB301_1_1 is transmitted from the transmission apparatus (terminal) inFIG. 28 during the first time.

The DFT-s-OFDM transmission region B301_1_2 in FIG. 30(A) is signalsobtained by performing processing on the DFT-s-OFDM symbol B201_1_2 inFIG. 29(A) and the DFT-s-OFDM symbol B201_2_2 in FIG. 29(B) at theprocessing unit B108 in FIG. 28. The DFT-s-OFDM transmission regionB301_1_2 is transmitted from the transmission apparatus during thesecond time.

The DFT-s-OFDM transmission region B301_1_3 in FIG. 30(A) is signalsobtained by performing processing on the DFT-s-OFDM symbol B201_1_3 inFIG. 29(A) and the DFT-s-OFDM symbol B201_2_3 in FIG. 29(B) at theprocessing unit B108 in FIG. 28. The DFT-s-OFDM transmission regionB301_1_3 is transmitted from the transmission apparatus during the thirdtime.

Thereafter, although omitted from illustration in FIG. 30(A), DFT-s-OFDMtransmission region B301_1_7 is signals obtained by performingprocessing on the DFT-s-OFDM symbol B201_1_7 (omitted from illustrationin FIG. 29(A)) and the DFT-s-OFDM symbol B201_2_7 (omitted fromillustration in FIG. 29(B)) at the processing unit B108 in FIG. 28. TheDFT-s-OFDM transmission region B301_1_7 is transmitted from thetransmission apparatus during the seventh time.

In the same way, the DFT-s-OFDM transmission region B301_2_1 in FIG.30(B) is signals obtained by performing processing on the DFT-s-OFDMsymbol B201_1_1 in FIG. 29(A) and the DFT-s-OFDM symbol B201_2_1 in FIG.29(B) at the processing unit B108 in FIG. 28. The DFT-s-OFDMtransmission region B301_2_1 is transmitted from the transmissionapparatus during the first time.

The DFT-s-OFDM transmission region B301_2_2 in FIG. 30(B) is signalsobtained by performing processing on the DFT-s-OFDM symbol B201_1_2 inFIG. 29(A) and the DFT-s-OFDM symbol B201_2_2 in FIG. 29(B) at theprocessing unit B108 in FIG. 28. The DFT-s-OFDM transmission regionB301_2_2 is transmitted from the transmission apparatus during thesecond time.

The DFT-s-OFDM transmission region B301_2_3 in FIG. 30(B) is signalsobtained by performing processing on the DFT-s-OFDM symbol B201_1_3 inFIG. 29(A) and the DFT-s-OFDM symbol B201_2_3 in FIG. 29(B) at theprocessing unit B108 in FIG. 28. The DFT-s-OFDM transmission regionB301_2_3 is transmitted from the transmission apparatus during the thirdtime.

Thereafter, although omitted from illustration in FIG. 30(B), DFT-s-OFDMtransmission region B301_2_7 is signals obtained by performingprocessing on the DFT-s-OFDM symbol B201_1_7 (omitted from illustrationin FIG. 29(A)) and the DFT-s-OFDM symbol B201_2_7 (omitted fromillustration in FIG. 29) at the processing unit B108 in FIG. 28. TheDFT-s-OFDM transmission region B301_2_7 is transmitted from thetransmission apparatus during the seventh time.

Accordingly, the DFT-s-OFDM transmission regions in FIG. 30(A) and FIG.30(B) include data transmission regions, DM-RS transmission regions, orPT-RS transmission regions.

The DFT-s-OFDM transmission region B301_1_1 in FIG. 30(A) and theDFT-s-OFDM transmission region B301_2_1 in FIG. 30(B) are transmittedfrom the transmission apparatus using a plurality of antennas (antennaunit #A and antenna unit #B), using the same frequency during the firsttime (same time). In the same way, the DFT-s-OFDM transmission regionB301_1_2 in FIG. 30(A) and the DFT-s-OFDM transmission region B301_2_2in FIG. 30(B) are transmitted from the transmission apparatus using aplurality of antennas (antenna unit #A and antenna unit #B), using thesame frequency during the second time (same time). Also, the DFT-s-OFDMtransmission region B301_1_3 in FIG. 30(A) and the DFT-s-OFDMtransmission region B301_2_3 in FIG. 30(B) are transmitted from thetransmission apparatus using a plurality of antennas (antenna unit #Aand antenna unit #B), using the same frequency during the third time(same time). Thereafter, in the same way, the DFT-s-OFDM transmissionregion B301_1_7 in FIG. 30(A) and the DFT-s-OFDM transmission regionB301_2_7 in FIG. 30(B) are transmitted from the transmission apparatususing a plurality of antennas (antenna unit #A and antenna unit #B),using the same frequency during the seventh time (same time).

Also, “CP” is added in FIG. 30(A) and FIG. 30(B). The cyclic prefixadding unit B117_A illustrated in FIG. 28 adds “CP” before theDFT-s-OFDM transmission region B301_1_1, as illustrated in FIG. 30(A).Thereafter, in the same way, the cyclic prefix adding unit B117_A adds“CP” before the DFT-s-OFDM transmission region B301_1_2, adds “CP”before the DFT-s-OFDM transmission region B301_1_3, . . . , and adds“CP” before the DFT-s-OFDM transmission region B301_1_7.

In the same way, the cyclic prefix adding unit B117_B illustrated inFIG. 28 adds “CP” before the DFT-s-OFDM transmission region B301_2_1, asillustrated in FIG. 30(B). Thereafter, in the same way, the cyclicprefix adding unit B117_B adds “CP” before the DFT-s-OFDM transmissionregion B301_2_2, adds “CP” before the DFT-s-OFDM transmission regionB301_2_3, . . . , and adds “CP” before the DFT-s-OFDM transmissionregion B301_2_7.

Note that the relation between “symbol” and “transmission region” in theDFT-s-OFDM symbols in FIG. 29(A) and FIG. 29B, and the DFT-s-OFDMtransmission regions in FIGS. 30(A) and 30(B) is the same as thatdescribed using “symbol” in FIG. 5A and FIG. 5B and “transmissionregion” in FIG. 7 and FIG. 8. That is to say, the DFT-s-OFDMtransmission region B301_1_k in FIG. 30(A) and the DFT-s-OFDMtransmission region B301_2_k in FIG. 30(B) are generated from theDFT-s-OFDM symbol B201_1_k during the k′th time in FIG. 29(A) and theDFT-s-OFDM symbol B201_2_k during the k′th time in FIG. 29(B). Examplesof the method of generating include Expression (1) through Expression(21) and so forth, but changing of transmission level using α1, α2, β1,and β2 does not have to be performed.

[Frame Configuration of DM-RS]

FIG. 31(A) and FIG. 31(B) illustrate a frame configuration example ofDM-RS symbols. In FIG. 31(A) and FIG. 31(B), the horizontal axis istime.

For example, a DM-RS symbol is transmitted in the DFT-s-OFDM symbolB201_1_4 transmitted by the transmission apparatus (terminal)illustrated in FIG. 28, at the fourth time in FIG. 29(A). FIG. 31(A)illustrates the state at that time, where a stream #1 DM-RS symbolB401_1 is the DFT-s-OFDM symbol B201_1_4 that the transmission apparatustransmits at the fourth time.

In the same way, a DM-RS symbol is transmitted in the DFT-s-OFDM symbolB201_2_4 transmitted by the transmission apparatus, at the fourth timein FIG. 29(B). FIG. 31(B) illustrates the state at that time, where astream #2 DM-RS symbol B401_2 is the DFT-s-OFDM symbol B201_2_4 that thetransmission apparatus transmits at the fourth time.

FIG. 32(A) and FIG. 32(B) illustrate a frame configuration example ofDM-RS transmission regions. In FIG. 32(A) and FIG. 32(B), the horizontalaxis is time.

From the description above, the DFT-s-OFDM transmission region B301_1_4that the transmission apparatus transmits during the fourth time in FIG.30(A) is a DM-RS transmission region. FIG. 32(A) illustrates the stateat that time, where a DM-RS transmission region B501_A of modulatedsignal A is the DFT-s-OFDM transmission region B301_1_4 that thetransmission apparatus transmits during the fourth time.

In the same way, the DFT-s-OFDM transmission region B301_2_4 that thetransmission apparatus transmits during the fourth time in FIG. 30(B) isa DM-RS transmission region. FIG. 32(B) illustrates the state at thattime, where a DM-RS transmission region B501_B of modulated signal B isthe DFT-s-OFDM transmission region B301_2_4 that the transmissionapparatus transmits during the fourth time.

Note that the relation between “symbol” and “transmission region” in thestream #1 DM-RS symbols and stream #2 DM-RS symbols in FIG. 31(A) andFIG. 31(B), and the DM-RS transmission regions of modulated signal A andthe DM-RS transmission regions of modulated signal B in FIGS. 32(A) and32(B) is the same as the relation described using “symbol” in FIG. 5Aand FIG. 5B and “transmission region” in FIG. 7 and FIG. 8. That is tosay, the DM-RS transmission regions of modulated signal A in FIG. 32(A)and the DM-RS transmission regions of modulated signal B in 32(B) aregenerated from the stream #1 DM-RS symbols in FIG. 31(A) and stream #2DM-RS symbols in FIG. 31B. Examples of the method of generating includeExpression (1) through Expression (21) and so forth, but changing oftransmission level using α1, α2, β1, and β2 does not have to beperformed.

[Configuration Example of DFT-s-OFDM Symbol and DFT-s-OFDM TransmissionRegion]

FIG. 33(A) and FIG. 33(B) illustrate a frame configuration example ofDFT-s-OFDM symbols during a k′th time (where k=1 through 3 and 5 through7). In FIG. 33(A) and FIG. 33(B), the horizontal axis is time.

For example, at least data symbols and PT-RS symbols are transmitted inthe DFT-s-OFDM symbols B201_1_1, B201_1_2, B201_1_3, B201_1_5, B201_1_6,and B201_1_7 where the transmission apparatus (terminal) transmitsduring the first time, second time, third time, fifth time, sixth time,and seventh time (i.e., times excluding the fourth time) in FIG. 29(A).FIG. 33(A) illustrates the state at that time, where the DFT-s-OFDMsymbol is configured of at least a stream #1 data symbol B601_1 and astream #1 PT-RS symbol B602_1. Note that symbols other than the stream#1 data symbol B601_1 and stream #1 PT-RS symbol B602_1 may be includedin the DFT-s-OFDM symbols. The stream #1 data symbol B601_1 isequivalent to the stream #1 baseband signals B107_1 in FIG. 28, andstream #1 PT-RS symbol B602_1 is included in the PT-RS (B103) in FIG.28.

In the same way, at least data symbols and PT-RS symbols are transmittedin the DFT-s-OFDM symbols B201_2_1, B201_2_2, B201_2_3, B201_2_5,B201_2_6, and B201_2_7 where the transmission apparatus (terminal)transmits during the first time, second time, third time, fifth time,sixth time, and seventh time (i.e., times excluding the fourth time) inFIG. 29(B). FIG. 33(B) illustrates the state at that time, where theDFT-s-OFDM symbol is configured of at least a stream #2 data symbolB601_2 and a stream #2 PT-RS symbol 602_2. Note that symbols other thanthe stream #2 data symbol B601_2 and stream #2 PT-RS symbol B602_2 maybe included in the DFT-s-OFDM symbols. The stream #2 data symbol B601_2is equivalent to the stream #2 baseband signals B107_2 in FIG. 28, andstream #2 PT-RS symbol B602_2 is included in the PT-RS signals B103 inFIG. 28.

FIG. 34(A) and FIG. 34(B) illustrate a configuration example ofDFT-s-OFDM transmission regions during a k′th time (where k=1 through 3and 5 through 7). In FIG. 34(A) and FIG. 34(B), the horizontal axis istime.

From the above description, the DFT-s-OFDM transmission regionsB301_1_1, B301_1_2, B301_1_3, B301_1_5, B301_1_6, and B301_1_7 which thetransmission apparatus transmits during the first time, second time,third time, fifth time, sixth time, and seventh time (i.e., timesexcluding the fourth time) in FIG. 30(A) are at least data transmissionregions of modulated signal A and PT-RS transmission regions ofmodulated signal A. FIG. 34(A) illustrates the state at that time, whereat least data transmission region B701_1 of modulated signal A and PT-RStransmission region B702_1 of modulated signal A are included in theDFT-s-OFDM transmission region B301_1_k that the transmission apparatustransmits during the k′th time (k=1, 2, 3, 5, 6, 7).

From the above description, the DFT-s-OFDM transmission regionsB301_2_1, B301_2_2, B301_2_3, B301_2_5, B301_2_6, and B301_2_7 which thetransmission apparatus transmits during the first time, second time,third time, fifth time, sixth time, and seventh time (i.e., timesexcluding the fourth time) in FIG. 30(B) are at least data transmissionregions of modulated signal B and PT-RS transmission regions ofmodulated signal B. FIG. 34(B) illustrates the state at that time, whereat least data transmission region B701_2 of modulated signal B and PT-RStransmission region B702_2 of modulated signal B are included in theDFT-s-OFDM transmission region B301_2_k that the transmission apparatustransmits during the k′th time (k=1, 2, 3, 5, 6, 7).

Note that the relation between “symbol” and “transmission region” in thestream #1 data symbols B601_1 and stream #2 data symbols B601_2 in FIG.33(A) and FIG. 33(B), and the data transmission region B701_1 ofmodulated signal A and the data transmission region B701_2 of modulatedsignal B in FIGS. 34(A) and 34(B) is the same as that described using“symbol” in FIG. 5A and FIG. 5B and “transmission region” in FIG. 7 andFIG. 8. That is to say, the data transmission region B701_1 of modulatedsignal A in FIG. 34(A) and the data transmission regions B701_2 ofmodulated signal B in 34(B) are generated from the stream #1 data symbolB601_1 at the k′th time in FIG. 33(A) and the stream #2 data symbolB601_2 at the k′th time in FIG. 33(B). Examples of the method ofgenerating include Expression (1) through Expression (21) and so forth,but changing of transmission level using α1, α2, β1, and β2 does nothave to be performed.

Also, the relation between “symbol” and “transmission region” in thestream #1 PT-RS symbol B602_1 and stream #2 data PT-RS symbol B602_2 inFIG. 33(A) and FIG. 33(B), and the PT-RS transmission region B702_1 ofmodulated signal A and the PT-RS transmission region B702_2 of modulatedsignal B in FIGS. 34(A) and 34(B) is the same as that described using“symbol” in FIG. 5A and FIG. 5B and “transmission region” in FIG. 7 andFIG. 8. That is to say, the PT-RS transmission region B702_1 in FIG.34(A) and the PT-RS transmission region B702_2 of modulated signal B in34(B) are generated from the stream #1 PT-RS symbol B602_1 at the k′thtime in FIG. 33(A) and the stream #2 PT-RS symbol B602_2 at the k′thtime in FIG. 33(B). Examples of the method of generating includeExpression (1) through Expression (21) and so forth, but changing oftransmission level using α1, α2, β1, and β2 does not have to beperformed.

[Signal Configuration Example After Adding Cyclic Prefix]

FIG. 35(A) and FIG. 35(B) illustrate a configuration example ofpost-cyclic-prefix-adding signals B118_A and B118_A that are the outputfrom the cyclic prefix adding units B117_A and B117_B in FIG. 28. InFIG. 35(A) and FIG. 35(B), the horizontal axis is time.

Note that configurations in FIG. 35(A) and FIG. 35(B) that are the sameas in FIG. 34(A) and FIG. 34(B) are denoted by the same referencenumerals, and description thereof will be omitted.

Now, FIG. 34(A) illustrates the DFT-s-OFDM transmission regionequivalent to the post-inverse-Fourier-transform signals B116_A in FIG.28, and FIG. 35(A) illustrates a configuration equivalent to thepost-cyclic-prefix-adding signals B118_A that are the output of thecyclic prefix adding unit B117_A in FIG. 28. Accordingly, the signalsillustrated in FIG. 35(A) are the signals illustrated in FIG. 34(A) towhich a cyclic prefix (i.e., CP (B801_1) of modulated signal A) has beenadded to the start.

In the same way, FIG. 34(B) illustrates the DFT-s-OFDM transmissionregion equivalent to the post-inverse-Fourier-transform signal B116_B inFIG. 28, and FIG. 35(B) illustrates a configuration equivalent to thepost-cyclic-prefix-adding signals B118_B that are the output of thecyclic prefix adding unit B117_B in FIG. 28. Accordingly, the signalsillustrated in FIG. 35(B) are the signals illustrated in FIG. 34(B) towhich a cyclic prefix (i.e., CP (B801_2) of modulated signal B) has beenadded to the start.

Now, taking into consideration the advantage of reduced computationscale at the transmission apparatus (terminal) in FIG. 28, i.e.,reduction in circuit scale, it is desirable that the inverse (fast)Fourier transform units (inverse discrete Fourier transform units)B115_A and B115_B perform inverse fast Fourier transform (IFFT: InverseFast Fourier Transform) rather than inverse discrete Fourier transform.

Taking this point into consideration, in FIG. 33(A), the sum of thesymbol count of stream #1 data symbols and the symbol count of stream #1PT-RS symbols preferably is 2^(n) symbols (where n is an integer of 1 orgreater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096,8192, 16384, 32768, 65536, and so on. Note that while “symbol” is usedhere, terms of “chip” and “sample” may be used for expression.

Accordingly, in FIG. 33(A), the sum of the chip count of stream #1 datasymbols (data chips) and the chip count of stream #1 PT-RS symbols(PT-RS chips) preferably is 2^(n) chips (where n is an integer of 1 orgreater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096,8192, 16384, 32768, 65536, and so on.

To rephrase this, in FIG. 33(A), the sum of the sample count of stream#1 data symbols (data samples) and the sample count of stream #1 PT-RSsymbols (PT-RS samples) preferably is 2^(n) samples (where n is aninteger of 1 or greater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024,2048, 4096, 8192, 16384, 32768, 65536, and so on.

In the same way, in FIG. 33(B), the sum of the symbol count of stream #2data symbols and the symbol count of stream #2 PT-RS symbols preferablyis 2^(n) symbols (where n is an integer of 1 or greater), such as 4, 8,16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536,and so on.

Accordingly, to rephrase this, in FIG. 33(B), the sum of the chip countof stream #2 data symbols (data chips) and the chip count of stream #2PT-RS symbols (PT-RS chips) preferably is 2^(n) chips (where n is aninteger of 1 or greater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024,2048, 4096, 8192, 16384, 32768, 65536, and so on.

To rephrase this further, in FIG. 33(B), the sum of the sample count ofstream #2 data symbols (data samples) and the sample count of stream #2PT-RS symbols (PT-RS samples) preferably is 2^(n) samples (where n is aninteger of 1 or greater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024,2048, 4096, 8192, 16384, 32768, 65536, and so on.

Accordingly, in FIG. 34(A), the sum of the chip count of datatransmission regions of modulated signal A and the chip count of PT-RStransmission regions of modulated signal A preferably is 2^(n) chips(where n is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128,256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

To rephrase this, in FIG. 34(A), the sum of the sample count of datatransmission regions of modulated signal A and the sample count of PT-RStransmission regions of modulated signal A preferably is 2^(n) samples(where n is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128,256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

In the same way, in FIG. 34(B), the sum of the chip count of datatransmission regions of modulated signal B and the chip count of PT-RStransmission regions of modulated signal B preferably is 2^(n) chips(where n is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128,256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

To rephrase this, in FIG. 34(B), the sum of the sample count of datatransmission regions of modulated signal B and the sample count of PT-RStransmission regions of modulated signal B preferably is 2^(n) samples(where n is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128,256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

[Method of Placing PT-RS Transmission Region in DFT-s-OFDM TransmissionRegion]

Next, a method of placing PT-RS transmission regions in the DFT-s-OFDMtransmission regions illustrated in FIG. 34(A) and FIG. 34(B) will bedescribed with reference to FIG. 35(A) and FIG. 35(B).

Now, the time intervals of the CP (B801_1) of modulated signal A in FIG.35(A) and the CP (B801_2) of modulated signal B in FIG. 35(B) will beexpressed as “Tz”.

Also, the time interval of the PT-RS transmission region B702_1 ofmodulated signal A and the PT-RS transmission region B702_2 of modulatedsignal B will be expressed as “T1”, as illustrated in FIG. 35(A) andFIG. 35(B).

Also, the time interval from a temporally last timing B850 of the PT-RStransmission region B702_1 of modulated signal A and the PT-RStransmission region B702_2 of modulated signal B, to a timing B852, willbe expressed as “T2” (B802). T2<T1 holds here.

Also, the time interval from the temporally last timing B850 of thePT-RS transmission region B702_1 of modulated signal A and the PT-RStransmission region B702_2 of modulated signal B, to a timing B853, willbe expressed as “T3” (B803). T3=T1 holds here.

Also, the time interval from the temporally last timing B850 of thePT-RS transmission region B702_1 of modulated signal A and the PT-RStransmission region B702_2 of modulated signal B, to a timing B854, willbe expressed as “T4” (B804). T4>T1 holds here.

That is to say, the time interval T2 is shorter than the time intervalT1 of the PT-RS transmission region, the time interval T3 is equal tothe time interval T1 of the PT-RS transmission region, and the timeinterval T4 is longer than the time interval T1 of the PT-RStransmission region.

Cases where the time interval Tz of the CP (B801_1) of the modulatedsignal A and the CP (B801_2) of the modulated signal B is time intervalT2, T3, and T4, will each be described.

<Case where Tx=T2>

In a case where the time interval Tz=T2 for the CP (B801_1) of themodulated signal A, the cyclic prefix adding unit B117_A copies thetemporal waveform of the time interval T2 in FIG. 35(A), and takes thisas the temporal waveform of the CP (B801_1) of the modulated signal A.In the same way, the time interval Tz is T2 for the CP (B801_2) of themodulated signal B as well, so the cyclic prefix adding unit B117_Bcopies the temporal waveform of the time interval T2 in FIG. 35(B), andtakes this as the temporal waveform of the CP (B801_2) of the modulatedsignal B.

In this case, the CP (B801_1) of the modulated signal A is configured ofpart of the PT-RS transmission region B702_1 of modulated signal A. Inthe same way, the CP (B801_2) of the modulated signal B is configured ofpart of the PT-RS transmission region B702_2 of modulated signal B.

Accordingly, the reception apparatus (base station) (omitted fromillustration) that is the communication partner of the transmissionapparatus (terminal) in FIG. 28 can handle both the CP (B801_1) of themodulated signal A and CP (B801_2) of the modulated signal B in the sameway as PT-RS transmission regions. Thus, the advantage of improved phasenoise estimation precision can be obtained from the reception apparatus(base station). Also, the reception apparatus will be able to use bothof the CP (B801_1) of the modulated signal A and CP (B801_2) of themodulated signal B for time synchronization, frequency synchronization,frequency offset estimation, signal detection, and so forth. This isparticularly advantageous in a case where PT-RS symbols are knownsignals to the transmission apparatus and reception apparatus.

<Case where Tx=T3>

In a case where the time interval Tz=T3 for the CP (B801_1) of themodulated signal A, the cyclic prefix adding unit B117_A copies thetemporal waveform of the time interval T3 in FIG. 35(A), and takes thisas the temporal waveform of the CP (B801_1) of the modulated signal A.In the same way, the time interval Tz is T3 for the CP (B801_2) of themodulated signal B as well, so the cyclic prefix adding unit B117_Bcopies the temporal waveform of the time interval T3 in FIG. 35(B), andtakes this as the temporal waveform of the CP (B801_2) of the modulatedsignal B.

In this case, the CP (B801_1) of the modulated signal A is configured ofthe same temporal waveform as the PT-RS transmission region B702_1 ofmodulated signal A. In the same way, the CP (B801_2) of the modulatedsignal B is configured of the same temporal waveform as the PT-RStransmission region B702_2 of modulated signal B.

Accordingly, the reception apparatus (base station) (omitted fromillustration) that is the communication partner of the transmissionapparatus (terminal) in FIG. 28 can handle both the CP (B801_1) of themodulated signal A and CP (B801_2) of the modulated signal B in the sameway as PT-RS transmission regions. Thus, the advantage of improved phasenoise estimation precision can be obtained from the reception apparatus(base station). Also, the reception apparatus will be able to use bothof the CP (B801_1) of the modulated signal A and CP (B801_2) of themodulated signal B for time synchronization, frequency synchronization,frequency offset estimation, signal detection, and so forth. This isparticularly advantageous in a case where PT-RS symbols are knownsignals to the transmission apparatus and reception apparatus.

<Case where Tx=T4>

In a case where the time interval Tz=T4 for the CP (B801_1) of themodulated signal A, the cyclic prefix adding unit B117_A copies thetemporal waveform of the time interval T4 in FIG. 35(A), and takes thisas the temporal waveform of the CP (B801_1) of the modulated signal A.In the same way, the time interval Tz is T3 for the CP (B801_2) of themodulated signal B as well, so the cyclic prefix adding unit B117_Bcopies the temporal waveform of the time interval T4 in FIG. 35(B), andtakes this as the temporal waveform of the CP (B801_2) of the modulatedsignal B.

In this case, the CP (B801_1) of the modulated signal A is configured ofthe PT-RS transmission region of modulated signal A and part of the datatransmission region B701_1 of the modulated signal A. In the same way,the CP (B801_2) of the modulated signal B is configured of the PT-RStransmission region of modulated signal B702_2 and part of the datatransmission region B701_2 of the modulated signal B.

Accordingly, the reception apparatus (base station) (omitted fromillustration) that is the communication partner of the transmissionapparatus (terminal) in FIG. 28 can handle part of the CP (B801_1) ofthe modulated signal A and CP (B801_2) of the modulated signal B in thesame way as PT-RS transmission regions. Thus, the advantage of improvedphase noise estimation precision can be obtained from the receptionapparatus (base station). Also, the reception apparatus will be able touse part of the CP (B801_1) of the modulated signal A and part of the CP(B801_2) of the modulated signal B for time synchronization, frequencysynchronization, frequency offset estimation, signal detection, and soforth. This is particularly advantageous in a case where PT-RS symbolsare known signals to the transmission apparatus and reception apparatus.

Thus, in the transmission apparatus, placing the PT-RS transmissionregions (PT-RS symbols) at the last portion of the DFT-s-OFDMtransmission regions (DFT-s-OFDM symbols) of the modulated signalsenables the CPs to be configured of the PT-RS transmission regions(PT-RS symbols). Accordingly, the reception apparatus can use the CPs inphase noise estimation in addition to the PT-RS transmission regions(PT-RS symbols) included in the DFT-s-OFDM transmission regions(DFT-s-OFDM symbols), So precision of estimating phase noise can beimproved, and data transmission efficiency can be improved.

[Frame Configuration of Signals After Adding Cyclic Prefix]

FIG. 36(A) and FIG. 36(B) illustrate an example of the frameconfiguration of signals after adding the cyclic prefix described inFIG. 35(A) and FIG. 35(B). The horizontal axis is time in FIG. 36(A) andFIG. 36(B).

That is to say, FIG. 36(A) illustrates an example of the frameconfiguration of the post-cyclic-prefix-adding signals B118_A in FIG.28, and FIG. 36(B) illustrates an example of the frame configuration ofthe post-cyclic-prefix-adding signals B118_B in FIG. 28.

CPs (B901_A and B901_B) and DFT-s-OFDM transmission regions B902_A andB902_B are signals transmitted by the transmission apparatus (terminal)in FIG. 28 during the first time. CPs (B903_A and B903_B) and DFT-s-OFDMtransmission regions B904_A and B904_B are signals transmitted by thetransmission apparatus during the second time. CPs (B905_A and B905_B)and DFT-s-OFDM transmission regions B906_A and B906_B are signalstransmitted by the transmission apparatus during the third time.

The DFT-s-OFDM transmission regions B902_A, B904_A, and B906_A areconfigured of the data transmission region B701_1 of the modulatedsignal A and the PT-RS transmission region B702_1 of the modulatedsignal A in FIG. 35(A), for example. The CPs (B901_A, B903_A, andB905_A) are configured like the CP (B801_1) of the modulated signal A inFIG. 35(A).

In the same way, the DFT-s-OFDM transmission regions B902_B, B904_B, andB906_B are configured of the data transmission region B701_2 of themodulated signal B and the PT-RS transmission region B702_2 of themodulated signal B in FIG. 35(B), for example. The CPs (B901_B, B903_B,and B905_B) are configured like the CP (B801_2) of the modulated signalB in FIG. 35(B).

Hereinafter, the time intervals of the CPs (B901_A, B901_B, B903_A,B903_B, B905_A, and B905_B) in FIG. 36(A) and FIG. 36(B) will beexpressed as “Tz0”.

Cases where the time interval Tz0 of the CPs (B901_A, B901_B, B903_A,B903_B, B905_A, and B905_B) is time interval T2, T3, and T4, will eachbe described here, as described in FIG. 35(A) and FIG. 35(B).

<Case where Tz0=T2>

In this case, the CPs (B901_A, B901_B, B903_A, B903_B, B905_A, andB905_B) are configured of part of the PT-RS transmission regions of themodulated signal, as described in FIG. 35(A) and FIG. 35(B).

Accordingly, looking at the DFT-s-OFDM transmission region B902_A and CP(B903_A), for example, in FIG. 36(A), “PT-RS transmission region ofmodulated signal A included in DFT-s-OFDM transmission region B902_A(last part) (e.g., see FIG. 35(A))” and “CP (B903_A) configured only ofPT-RS transmission region of modulated signal A” are consecutive.Accordingly, the temporally-consecutive PT-RS transmission region isexpanded. This point is the same regarding the consecutive region madeup of the DFT-s-OFDM transmission region B904_A and CP (B905_A), and soforth.

In the same way, looking at the DFT-s-OFDM transmission region B902_Band CP (B903_B), for example, in FIG. 36(B), “PT-RS transmission regionof modulated signal B included in DFT-s-OFDM transmission region B902_B(last part) (e.g., see FIG. 35(B)” and “CP (B903_B) configured only ofPT-RS transmission region of modulated signal B” are consecutive.Accordingly, the temporally-consecutive PT-RS transmission region isexpanded. This point is the same regarding the consecutive region madeup of the DFT-s-OFDM transmission region B904_B and CP (B905_B), and soforth.

Accordingly, an advantage can be obtained in that the receptionapparatus (base station) that is the communication partner of thetransmission apparatus (terminal) in FIG. 28 can estimate phase noisewith high precision using the temporally-consecutive PT-RS transmissionregions and CPs (configured of PT-RS transmission regions), and can alsoperform highly precise channel estimation, time synchronization,frequency synchronization, frequency offset estimation, and signaldetection.

<Case where Tz0=T3>

In this case, the CPs (B901_A, B901_B, B903_A, B903_B, B905_A, andB905_B) are configured of the same temporal waveform as the PT-RStransmission regions of the modulated signal, as described in FIG. 35(A)and FIG. 35(B).

Accordingly, looking at the DFT-s-OFDM transmission region B902_A and CP(B903_A), for example, in FIG. 36(A), “PT-RS transmission region ofmodulated signal A included in DFT-s-OFDM transmission region B902_A(last part) (e.g., see FIG. 35(A)” and “CP (B903_A) configured only ofPT-RS transmission region of modulated signal A” are consecutive.Accordingly, the temporally-consecutive PT-RS transmission region isexpanded. This point is the same regarding the consecutive region madeup of the DFT-s-OFDM transmission region B904_A and CP (B905_A), and soforth.

In the same way, looking at the DFT-s-OFDM transmission region B902_Band CP (B903_B), for example, in FIG. 36(B), “PT-RS transmission regionof modulated signal B included in DFT-s-OFDM transmission region B902_B(last part) (e.g., see FIG. 35(B)” and “CP (B903_A) configured only ofPT-RS transmission region of modulated signal B” are consecutive.Accordingly, the temporally-consecutive PT-RS transmission region isexpanded. This point is the same regarding the consecutive region madeup of the DFT-s-OFDM transmission region B904_B and CP (B905_B), and soforth.

Accordingly, an advantage can be obtained in that the receptionapparatus (base station) can estimate phase noise with high precisionusing the temporally-consecutive PT-RS transmission regions and CPs(configured of PT-RS transmission regions), and can also perform highlyprecise channel estimation, time synchronization, frequencysynchronization, frequency offset estimation, and signal detection.

<Case where Tz0=T4>

In this case, the CPs (B901_A, B901_B, B903_A, B903_B, B905_A, andB905_B) are configured of the PT-RS transmission regions of themodulated signal and part of the data transmission regions of themodulated signal, as described in FIG. 35(A) and FIG. 35(B).

Accordingly, looking at the DFT-s-OFDM transmission region B902_A and CP(B903_A), for example, in FIG. 36(A), “PT-RS transmission region ofmodulated signal A included in DFT-s-OFDM transmission region B902_A”and “CP (B903_A) configured of PT-RS transmission region and datatransmission region of modulated signal A” are consecutive. At thistime, this temporally-consecutive region has “PT-RS transmissionregion”, “data transmission region”, and “PT-RS transmission region”arrayed in that order. Thus, there is a feature in that “PT-RStransmission regions” are non-consecutive.

In the same way, looking at the DFT-s-OFDM transmission region B902_Band CP (B903_B), for example, in FIG. 36(B), “PT-RS transmission regionof modulated signal B included in DFT-s-OFDM transmission region B902_B”and “CP (B903_B) configured of PT-RS transmission region and datatransmission region of modulated signal B” are consecutive. At thistime, this temporally-consecutive region has “PT-RS transmissionregion”, “data transmission region”, and “PT-RS transmission region”arrayed in that order. Thus, there is a feature in that “PT-RStransmission regions” are non-consecutive.

Note however, that in the case where Tz0=T4, the reception apparatus(base station) can use CPs in estimation of phase noise, in addition tothe PT-RS transmission regions (PT-RS symbols), as described withreference to FIG. 35(A) and FIG. 35(B), so an advantage can be obtainedin that phase noise can be estimated with high precision, and highlyprecise channel estimation, time synchronization, frequencysynchronization, frequency offset estimation, and signal detection canalso be performed.

Description has been made above regarding each case where the timeinterval Tz0 of the CPs (B901_A, B901_B, B903_A, B903_B, B905_A, andB905_B) is T2, T3, and T4.

For example, the transmission apparatus (terminal) in FIG. 28 can selectbetween the transmission in FIG. 36(A) and FIG. 36(B), and thetransmission in FIG. 37(A) and FIG. 37(B).

Note that configurations in FIG. 37(A) and FIG. 37(B) that are the sameas in FIG. 36(A) and FIG. 36(B) are denoted by the same referencenumerals, and description thereof will be omitted. FIG. 37(A) differsfrom FIG. 36(A) with regard to the point that extended CPs (B1001_A,B1003_A, and B1005_A) have been added instead of the CPs (B901_A,B903_A, and B905_A) in FIG. 36(A). In the same way, FIG. 37(B) differsfrom FIG. 36(B) with regard to the point that extended CPs (B1001_B,B1003_B, and B1005_B) have been added instead of the CPs (B901_B,B903_B, and B905_B) in FIG. 36(B).

The method of adding extended CPs is the same as the method describedwith reference to FIG. 35(A) and FIG. 35(B).

In FIG. 37(A) and FIG. 37(B), the time interval of the CPs (B1001_A,B1001_B, B1003_A, B1003_B, B1005_A, and B1005_B) is “Tz1”. Tz1>Tz0 holdshere.

The benefits and advantages in a case of setting the CP time intervalTz0 in FIG. 36(A) and FIG. 36(B) to T2 (see FIG. 35) and to T3 (se FIG.35) here is as described above. In the same way, in a case of settingthe extended CP time interval Tz1 in FIG. 37(A) and FIG. 37(B) to T2,the temporally-consecutive PT-RS transmission regions can be extended inthe same way as where Tz0=T2, so the above described benefits andadvantages can be obtained. Also, in a case of setting the extended CPtime interval Tz1 in FIG. 37(A) and FIG. 37(B) to T3, thetemporally-consecutive PT-RS transmission regions can be extended in thesame way as where Tz0=T3, so the above described benefits and advantagescan be obtained.

Accordingly, in a case where the transmission apparatus (terminal)illustrated in FIG. 28 is capable of selecting between transmission inFIG. 36(A) and FIG. 36(B), and transmission in FIG. 37(A) and FIG.37(B), Tz1>Tz0 holds, so the transmission apparatus can obtain theabove-described benefits and advantages by satisfying one of Tz1=T2 orTz1=T3, regardless of whether performing the transmission in FIG. 37(A)and FIG. 37(B) or the transmission in FIG. 36(A) and FIG. 36(B).

The following will be further studied.

An arrangement is made where the transmission apparatus can select oneof n methods, from a method where the CP time width (time interval) hasa first time width to a method where the CP time width has an n'th timewidth, and transmit a modulated signal. Note that n is an integer of 2or greater. Also, a k′th time width is represented by “Tzk”. Note that kis an integer of 1 or greater but n or smaller. Of all ks, the greatestvalue of Tzk is represented by “Tzmax”.

In a case where one of Tzmax=T2 or Tzmax=T3 is satisfied, thetemporally-consecutive PT-RS transmission regions can be extended,regardless of which of the method where the CP time width has a firsttime width through the method where the CP time width has an n'th timewidth the transmission apparatus selects, so the above-describedbenefits and advantages can be obtained.

Next, a case where the transmission apparatus (terminal) in FIG. 28transmits modulated signals in FIG. 38(A) and FIG. 38(B) will bedescribed.

Note that configurations in FIG. 38(A) and FIG. 38(B) that are the sameas in FIG. 36(A) and FIG. 36(B) are denoted by the same referencenumerals, and description thereof will be omitted.

FIG. 38(A) differs from FIG. 36(A) with regard to the point that a firstCP (B1101_A), and second CPs (B1103_A and B1105_A), have been addedinstead of the CPs (B901_A, B903_A, and B905_A) in FIG. 36(A). In thesame way, FIG. 38(B) differs from FIG. 36(B) with regard to the pointthat a first CP (B1101_B), and second CPs (B1103_B and B1105_B), havebeen added instead of the CPs (B901_B, B903_B, and B905_B) in FIG.36(B).

The method of adding first CPs and second CPs is the same as the methoddescribed with reference to FIG. 35(A) and FIG. 35(B).

In FIG. 38(A) and FIG. 38(B), the time interval of the first CPs(B1101_A, B1101_B) is represented by “Ty1”, and the time interval of thesecond CPs (B1103_A, B1105_A, B1103_B, and B1105_B) is represented by“Ty2”. Ty1>Ty2 holds here.

At this time, by setting Ty1=T2 or Ty1=T3 for the first CP time intervalin FIG. 38(A) and FIG. 38(B), the temporally-consecutive PT-RStransmission regions can be extended at either boundary of “DFT-s-OFDMtransmission regions” and “CPs (first CP and second CP)” due to therelation of Ty1>Ty2, and the above-described benefits and advantages canbe obtained.

A DFT-s-OFDM transmission region is present temporally before the firstCP (B1101_A). This DFT-s-OFDM transmission region is configured of aDM-RS transmission region, or a data transmission region and PT-RStransmission region. Accordingly, the above-described benefits andadvantages can be obtained.

Also, by setting Ty2=T2 or Ty2=T3 for the second CP time interval inFIG. 38(A) and FIG. 38(B), the temporally-consecutive PT-RS transmissionregions can be extended at either boundary of “DFT-s-OFDM transmissionregions” and “second CPs”, and the above-described benefits andadvantages can be obtained.

The following will be further studied.

An arrangement is made where the transmission apparatus transmits CPs ofn methods, from a method where the CP time width has a first time widthto a method where the CP time width has an n'th time width. Note that nis an integer of 2 or greater. Also, a k′th time width is represented by“Tyk”. Note that k is an integer of 1 or greater but n or smaller. Ofall ks, the greatest value of Tyk is represented by “Tymax”.

In a case where one of Tymax=T2 or Tymax=T3 is satisfied, thetemporally-consecutive PT-RS transmission regions can be extended withany CP of a CP having the first time width through a CP having an n'thtime width, so the above-described benefits and advantages can beobtained.

Thus, in the present embodiment, the transmission apparatus (terminal)maps PT-RS transmission regions at the end of DFT-s-OFDM transmissionregions transmitted each transmission time (k′th time). Accordingly, thetransmission apparatus can copy the temporal waveforms of the PT-RStransmission region in each transmission time, and add a CP.

Accordingly, in each transmission time (symbol), a reception apparatus(e.g., base station) can use CPs for estimation of phase noise, inaddition to the PT-RS transmission regions included in the DFT-s-OFDMtransmission regions, so the precision of estimating phase noise can beimproved.

Also, the reception apparatus can extend PT-RS transmission regionsregarding time region by the PT-RS transmission regions included inDFT-s-OFDM transmission regions and the subsequent CPs, in frames whereDFT-s-OFDM transmission regions have been placed, so the precision ofestimating phase noise can be improved.

Thus, according to the present embodiment, the reception apparatus canimprove the precision of estimating phase noise, and data transmissionefficiency can be improved.

(First Modification)

Although the example illustrated in FIG. 33(A) has been described as aconfiguration example of the “DFT-s-OFDM symbol” in FIG. 29(A), theconfiguration of the “DFT-s-OFDM symbol” is not restricted to this. Forexample, the “DFT-s-OFDM symbol” may include a symbol other than the“stream #1 data symbol” and “stream #1 PT-TS symbol” illustrated in FIG.33(A). Note however, that the “stream #1 PT-TS symbol” preferably isplaced at the end portion of the “DFT-s-OFDM symbol”, as describedabove. Appropriate configuration method and configuration requisites(e.g., time width) for the “stream #1 PT-TS symbol” are as describedabove.

In the same way, although the example illustrated in FIG. 33(B) has beendescribed as a configuration example of the “DFT-s-OFDM symbol” in FIG.29(B), the configuration of the “DFT-s-OFDM symbol” is not restricted tothis. For example, the “DFT-s-OFDM symbol” may include a symbol otherthan the “stream #2 data symbol” and “stream #2 PT-TS symbol”illustrated in FIG. B6B. Note however, that the “stream #2 PT-TS symbol”preferably is placed at the end portion of the “DFT-s-OFDM symbol”, asdescribed above. Appropriate configuration method and configurationrequisites (e.g., time width) for the “stream 21 PT-TS symbol” are asdescribed above.

For example, in a “DFT-s-OFDM symbol”, a stream #1 PT-RS symbol(B1202_1) may be temporally placed before stream #1 data symbols(B1201_1 and B1203_1), as illustrated in FIG. 39(A). Note that asillustrated in FIG. 39(A), the stream #1 PT-TS symbol (B602_1)preferably is placed at the end portion of the DFT-s-OFDM symbol, in thesame way as in FIG. 33(A). Appropriate configuration method andconfiguration requisites (e.g., time width) for the “stream #1 PT-TSsymbol” are as described above.

In the same way, in a “DFT-s-OFDM symbol”, a stream #2 PT-RS symbol(B1202_2) may be temporally placed before stream #2 data symbols(B1201_2 and B1203_2), as illustrated in FIG. 39(B). Note that asillustrated in FIG. 39(B), the stream #1 PT-RS symbol (B602_2)preferably is placed at the end portion of the DFT-s-OFDM symbol, in thesame way as in FIG. 33(B). Appropriate configuration method andconfiguration requisites (e.g., time width) for the “stream #2 PT-TSsymbol” are as described above.

Taking the description of FIG. 33(A) and FIG. 33(B) into consideration,the symbol count of the DFT-s-OFDM symbols (B201_1_1, B201_2_1, andB201_1_3) and (B201_2_1, B201_2_2, and B201_2_3) in FIG. 29(A) and FIG.29(B) preferably is 2^(n) symbols (where n is an integer of 1 orgreater), such as 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096,8192, 16384, 32768, 65536, and so on. Note that while “symbol” is usedhere, terms of “chip” and “sample” may be used for expression.

Accordingly, taking the description of FIG. 33(A) and FIG. 33(B) intoconsideration, the symbol count (chip count) of the DFT-s-OFDM symbols(B201_1_1, B201_2_1, and B201_1_3) and (B201_2_1, B201_2_2, andB201_2_3) in FIG. 29(A) and FIG. 29(B) preferably is 2^(n) chips (wheren is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128, 256,512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

To rephrase this, taking the description of FIG. 33(A) and FIG. 33(B)into consideration, the symbol count (sample count) of the DFT-s-OFDMsymbols (B201_1_1, B201_2_1, and B201_1_3) and (B201_2_1, B201_2_2, andB201_2_3) in FIG. 29(A) and FIG. 29(B) preferably is 2^(n) samples(where n is an integer of 1 or greater), such as 4, 8, 16, 32, 64, 128,256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, and so on.

Also, although an example illustrated in FIG. 34(A) has been describedas an example of the configuration of “DFT-s-OFDM transmission region”in FIG. 30(A), the configuration of “DFT-s-OFDM transmission region” isnot restricted to this in the present embodiment. For example, the“DFT-s-OFDM transmission region” may include transmission regions otherthan the “data transmission region of modulated signal A” and “PT-RStransmission region of modulated signal A” illustrated in FIG. 34(A).Note however, that the “PT-TS transmission region of modulated signal A”preferably is placed at the end portion of the “DFT-s-OFDM transmissionregion” as described above. Appropriate configuration method andconfiguration requisites (e.g., time width) for the “PT-RS transmissionregion of modulated signal A” are as described above.

In the same way, although an example illustrated in FIG. 34(B) has beendescribed as an example of the configuration of “DFT-s-OFDM transmissionregion” in FIG. 30(B), the configuration of “DFT-s-OFDM transmissionregion” is not restricted to this. For example, the “DFT-s-OFDMtransmission region” may include transmission regions other than the“data transmission region of modulated signal B” and “PT-RS transmissionregion of modulated signal B” illustrated in FIG. 34(B). Note however,that the “PT-TS transmission region of modulated signal B” preferably isplaced at the end portion of the “DFT-s-OFDM transmission region” asdescribed above. Appropriate configuration method and configurationrequisites (e.g., time width) for the “PT-RS transmission region ofmodulated signal B” are as described above.

For example, in a “DFT-s-OFDM transmission region”, a PT-RS transmissionregion of modulated signal A (B1302_1) may be temporally placed beforedata transmission regions of modulated signal A (B1301_1 and B1303_1),as illustrated in FIG. 40(A). Note that as illustrated in FIG. 40(A),the PT-TS transmission region of modulated signal A (B702_1) preferablyis placed at the end portion of the DFT-s-OFDM transmission region, inthe same way as in FIG. 34(A). Appropriate configuration method andconfiguration requisites (e.g., time width) for the “PT-TS transmissionregion for modulated signal A” are as described above.

In the same way, in a “DFT-s-OFDM transmission region”, a PT-RStransmission region of modulated signal B (B1302_2) may be temporallyplaced before data transmission regions of modulated signal B (B1301_2and B1303_2), as illustrated in FIG. 40(B). Note that as illustrated inFIG. 40(B), the PT-TS transmission region of modulated signal B (B702_2)preferably is placed at the end portion of the DFT-s-OFDM transmissionregion, in the same way as in FIG. 34(B). Appropriate configurationmethod and configuration requisites (e.g., time width) for the “PT-TStransmission region for modulated signal B” are as described above.

(Second Modification)

Although MIMO transmission (where a plurality of streams are transmittedusing a plurality of antennas) has been described in the aboveembodiment, the transmission format is not restricted to MIMOtransmission.

For example, the transmission apparatus (terminal) illustrated in FIG.28 may apply a single-stream transmission method.

In this case, at the modulated signal generator B106 illustrated in FIG.28, for example, the baseband signals B107_1 (stream #1) and thebaseband signals B107_2 (stream #2) are the same stream.

An example will be described regarding this point.

For example, the baseband signals B107_1 and the baseband signals B107_2may be the same modulated signal.

As another example, in a case where a first bit sequence is beingtransmitted by the baseband signals B107_1, the first bit sequence istransmitted at the baseband signals B107_2 as well.

As another example, assumption will be made that a first symbol thattransmits a first bit sequence exists in the baseband signals B107_1. Atthis time, a symbol that transmits a first bit sequence exists in thebaseband signals B107_2.

The baseband signals B107_1 and B107_2 that are the same stream may betransmitted from the antenna unit #A (B121_A) and antenna unit #B(B121_B) that are different, or the baseband signals B107_1 and B107_2may be transmitted from a plurality of antennas.

Alternatively, an arrangement may be made where, at the modulated signalgenerator B106 illustrated in FIG. 28, for example, only the basebandsignal B107_1 (stream #1) is output, the modulated signal B109_A isoutput from the processing unit B108, and the modulated signal B109_A istransmitted from one antenna unit #A (B121_A). That is to say, singleantenna transmission of a single stream is executed by the modulatedsignal generator B106 and processing unit B108 outputting modulatedsignals corresponding to the configuration of one antenna system (e.g.,discrete Fourier transform unit B100_A through antenna unit B121_A).Note that precoding is not performed at the processing unit B108 at thistime.

Alternatively, an arrangement may be made where, at the modulated signalgenerator B106 illustrated in FIG. 28, for example, wherein only thebaseband signal B107_1 (stream #1) is output, modulated signals B109_Aand B109_B subjected to CDD at the processing unit B108 are output, andthe modulated signals B109_A and B109_B are transmitted from the two ofthe antenna unit #A (B121_A) and antenna unit #B (B121_B), respectively.That is to say, multi-antenna transmission of a single stream isexecuted by the processing unit B108 outputting modulated signalscorresponding to the configuration of two antenna systems (e.g.,discrete Fourier transform unit B110 through antenna unit B121) withregard to one baseband signal output from the modulated signal generatorB106.

Advantages the same as the examples described in the present embodimentcan be obtained with regard to a case where the terminal transmitssingle-stream modulated signals, as described above. For example,arrangements may be made where the terminal transmits FIG. 29(A) out ofFIG. 29(A) and FIG. 29(B), the terminal transmits FIG. 30(A) out of FIG.30(A) and FIG. 30(B), the terminal transmits FIG. 31(A) out of FIG.31(A) and FIG. 31(B), the terminal transmits FIG. 32(A) out of FIG.32(A) and FIG. 32(B), the terminal transmits FIG. 33(A) out of FIG.33(A) and FIG. 33(B), the terminal transmits FIG. 34(A) out of FIG.34(A) and FIG. 34(B), the terminal transmits FIG. 35(A) out of FIG.35(A) and FIG. 35(B), the terminal transmits FIG. 36(A) out of FIG.36(A) and FIG. 36(B), the terminal transmits FIG. 37(A) out of FIG.37(A) and FIG. 37(B), the terminal transmits FIG. 38(A) out of FIG.38(A) and FIG. 38(B), the terminal transmits FIG. 39(A) out of FIG.39(A) and FIG. 39(B), and the terminal transmits FIG. 40(A) out of FIG.40(A) and FIG. 40(B). Appropriate transmission method, frameconfiguration method, configuration requisites (e.g., time width), andso forth, are as described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 29(A) and FIG. 29(B). The method of generating themodulated signals in FIG. 29(A) and FIG. 29(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 30(A) and FIG. 30(B). The method of generating themodulated signals in FIG. 30(A) and FIG. 30(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 31(A) and FIG. 31(B). The method of generating themodulated signals in FIG. 31(A) and FIG. 31(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 32(A) and FIG. 32(B). The method of generating themodulated signals in FIG. 32(A) and FIG. 32(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 33(A) and FIG. 33(B). The method of generating themodulated signals in FIG. 33(A) and FIG. 33(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 34(A) and FIG. 34(B). The method of generating themodulated signals in FIG. 34(A) and FIG. 34(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 35(A) and FIG. 35(B). The method of generating themodulated signals in FIG. 35(A) and FIG. 35(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 36(A) and FIG. 36(B). The method of generating themodulated signals in FIG. 36(A) and FIG. 36(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 37(A) and FIG. 37(B). The method of generating themodulated signals in FIG. 37(A) and FIG. 37(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 38(A) and FIG. 38(B). The method of generating themodulated signals in FIG. 38(A) and FIG. 38(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 39(A) and FIG. 39(B). The method of generating themodulated signals in FIG. 39(A) and FIG. 39(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

The terminal also may transmit single-stream modulated signals of theconfiguration in FIG. 40(A) and FIG. 40(B). The method of generating themodulated signals in FIG. 40(A) and FIG. 40(B) at this time is asdescribed above. Appropriate transmission method, frame configurationmethod, configuration requisites (e.g., time width), and so forth, areas described above.

Embodiments of the present disclosure have been described above.

It is needless to say that a plurality of embodiments and other contentsdescribed in the present specification may be combined and implemented.

The embodiments are only examples, so for example, even if “modulationscheme, error correction encoding format (error correction code used,code length, encoding efficiency, etc.) control information, and soforth” is exemplified, the same configuration can implement applicationto a different “modulation scheme, error correction encoding format(error correction code used, code length, encoding efficiency, etc.)control information, and so forth”.

With regard to the modulation scheme, the embodiments and other contentsdescribed in the present specification can be implemented even if amodulation scheme other than a modulation scheme described in thepresent specification is used. For example, APSK (Amplitude Phase ShiftKeying) (e.g., 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK, 4096APSK.Etc.), PAM (Pulse Amplitude Modulation) (e.g., 4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 1024PAM, 4096PAM, etc.), PSK (Phase Shift Keying)(e.g., BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK, 1024PSK, 4096PSK,etc.), QAM (Quadrature Amplitude Modulation) (e.g., 4 QAM, 8QAM, 16QAM,64QA, 128QAM, 256QAM, 1024QAM, 4096QAM etc.) or the like may be applied,and uniform mapping or non-uniform mapping may be used in eachmodulation scheme.

Also, a layout method of 2, 4, 8, 16, 64, 128, 256, 1024, and so forth,signal points on an I-Q plane (modulation scheme having 2, 4, 8, 16, 64,128, 256, 1024, and so forth, signal points) is not restricted to thesignal point layout method of the modulation scheme shown in the presentspecification. Accordingly, functions of outputting in-phase componentsand orthogonal components based on a plurality of bits are the functionsat the mapping unit, and the subsequently-performed precoding and phasechange is an effective function according to an aspect of the presentdisclosure.

Also, in a case where there is a complex plane, increments of phase suchas the argument is expressed as “radian” in the present specification.Using a complex plane allows expression in polar form, as an expressionby polar coordinates of a complex number. When a point (a, b) on thecomplex plane is associated with a complex number z=a+jb (where a and bare both real numbers and j is an imaginary unit), and this point isexpressed in polar coordinates as [r, θ],a=r×cos θ,b=r×sin θandr=√{square root over (a ² +b ²)}  [Math 32]hold, with r being the absolute value of z (r=|z|), and θ being theargument. z=a+jb is then expressed as r×e^(jθ).

A configuration may be made in the present specification where thereception apparatus and antenna are separate. For example, the receptionapparatus has an interface that inputs, via a cable, signals which aresignals received at the antenna, or signals received at the antenna andsubjected to frequency conversion, and the reception apparatus performssubsequent processing. Data/information that the reception apparatus hasobtained is later converted into video or audio, and displayed on adisplay (monitor) or output from a speaker as sound. Thedata/information that the reception apparatus has obtained may besubjected to signal processing related to video or audio (or does nothave to be subjected to signal processing) and output from RCA terminals(video terminal and audio terminals), USB (Universal Serial Bus), HDMI(a registered trademark) (High-Definition Multimedia Interface), digitalterminal, or the like.

In the present specification, it is conceivable that the transmissionapparatus is provided to, for example, a broadcast station, basestation, access point, terminal, cellular phone (mobile phone), andother such communication/broadcast equipment, and at this time, it isconceivable that the reception apparatus is provided to a televisionset, radio, terminal, personal computer cellular phone, access point,base station, and other such communication equipment. It is alsoconceivable in the present disclosure that the transmission apparatusand reception apparatus is equipment having communication functions,with the equipment having a form of being connected to a apparatus forexecuting an application, such as a television set, radio, personalcomputer, cellular phone, or the like, via some sort of interface.Embodiments have been described in the present specification using thenames of base station and terminal, but these are only examples, andwhat is called “base station” in the embodiments may be called by othernames (e.g., access point, terminal, cellular phone, personal computer,etc.), and what is called “terminal” in the embodiments may be called byother names (e.g., access point, base station, cellular phone, personalcomputer, etc.).

Also, in the embodiments above, symbols other than data symbols, e.g.,pilot symbols (preamble, unique word, postamble, reference symbol,etc.), symbols for control information, and so forth, may be laid outany way in a frame. Although the names of pilot symbols and symbols forcontrol information have been given here, any sort of naming may beused, and what is important are the functions themselves.

It is sufficient for pilot symbols to be, for example, a known symbolmodulated using PSK modulation at the transmission/reception apparatus(or it is sufficient for the reception apparatus to be able to know thesymbol transmitted by the transmission apparatus by the receptionapparatus performing synchronization), and the reception apparatus usesthis symbol to perform frequency synchronization, time synchronization,channel estimation (estimation of CSI (Channel State Information)) (ofthe modulated signal), signal detection, and so forth.

Also, symbols for control information are symbols for transmittinginformation that needs to be transmitted to a communication partner(e.g., modulation scheme, error correction encoding format, and encodingefficiency of error correction encoding format, used in communication,settings information of upper layer, etc.), in order to realizecommunication of other than data (of an application or the like).

Note that the present disclosure is not restricted to the embodiments,and be carried out with various alterations made. For example, theembodiments describe a case being carried out as a communicationapparatus, but this is not restrictive, and this communication methodmay be carried out as software.

Although a precoding switching method in a method of transmitting twomodulated signals from two antennas has been described in the aboveembodiments, this is not restrictive, and this can be carried out in thesame way as a precoding switching method where a precoding weight(matrix) is changed in a method of performing precoding on fourpost-mapping signals to generate four modulated signals and transmitfrom four antennas, i.e., a method of performing precoding on Npost-mapping signals to generate N modulated signals and transmit from Nantennas, in the same way.

Although terms such as “precoding”, “precoding weight”, and so forth areused in the present specification, the names themselves are irrelevant,with the signal processing itself being important in the presentdisclosure.

One antenna illustrated in the drawings may be configured of a pluralityof antennas, for both the transmitting antenna of the transmissionapparatus and the receiving antenna of the reception apparatus.

With regard to the transmission apparatus and reception apparatus, thereception apparatus, which is dependent on a frame that the transmissionapparatus transmits, omitted depending on the embodiment, that isnecessary for notification of the transmission method (MIMO, SISO,space-time block code, interleaving format), modulation scheme, or errorcorrection encoding format, receives the same, and operations arechanged.

Also, an arrangement may be made where a program for executing the abovecommunication method, for example, is stored in ROM (Read Only Memory)beforehand, and a CPU (Central Processor Unit) runs the program.

The program that executes the above communication method may be storedin a computer-readable storage medium, and the program stored in thestorage medium recorded in RAM (Random Access Memory) of a computer, andthe computer made to operate in accordance with the program.

The configurations such as the above embodiments typically areconfigured as LSI (Large Scale Integration) that is an integratedcircuit. These may be individually formed into one chip, or part or allof configurations of the embodiments may be included in one chip. Whiledescription has been made here regarding an LSI, there are differentnames such as IC (Integrated Circuit), system LSI, super LSI, and ultraLSI, depending on the degree of integration. The circuit integrationtechnique is not restricted to LSIs, and dedicated circuits orgeneral-purpose processors may be used to realize the same. An FPGA(Field Programmable Gate Array) which can be programmed aftermanufacturing the LSI, or a reconfigurable processor where circuit cellconnections and settings within the LSI can be reconfigured, may beused.

Further, in the event of the advent of an integrated circuit technologywhich would replace LSIs by advance of semiconductor technology or aseparate technology derived therefrom, such a technology may be used forintegration of the functional blocks, as a matter of course. Applicationof biotechnology is a possibility.

The present disclosure is broadly applicable to wireless systems wheredifferent modulated signals are transmitted from a plurality ofantennas. For example, this is suitable for application to asingle-carrier MIMO communication system and an OFDM-MIMO communicationsystem. This is also applicable to cases of performing MIMO transmissionin a wired communication system having a plurality of transmissionlocations (e.g., PLC (Power Line Communication) system, opticalcommunication system, DSL (Digital Subscriber Line: digital subscriberline) system), and communication systems using light or visible light.

Also, in the present specification, the reception apparatus that is thecommunication partner may perform channel estimation by PT-RStransmission regions (PT-RS symbols). The reception apparatus that isthe communication partner may also perform phase noise estimation byDM-RS transmission regions (DM-RS symbols).

Other distortion estimation may be performed by PT-RS transmissionregions (PT-RS symbols) or DM-RS transmission regions (DM-RS symbols).For example, estimation of intercarrier interference, estimation ofinter-symbol interference, estimation of frequency offset, timesynchronization, frequency synchronization, and signal detection may beperformed.

The number of antennas that transmit modulated signals is not restrictedto the number of antennas illustrated in the drawings of the presentspecification. The embodiments can be carried out in the same way aslong as the number of antennas is one or more. Each antenna may be madeup of a plurality of antennas.

Although terms such as DM-RS and PT-RS have been used in the presentspecification, the names are not restricted to this. Any names may beused, such as for example, reference signals (RS: Reference Signal),pilot signals, pilot symbols, reference signals, channel estimationsymbols, unique words, and so forth.

INDUSTRIAL APPLICABILITY

The resent disclosure is useful in communication apparatuses such asbase stations and terminals.

REFERENCE SIGNS LIST

-   -   104_1 through 104_n user #1 modulated signal generator through        user #n modulated signal generator    -   107_A, 107_B multiplexer (signal processing unit)    -   109_A, 109_B, 703X, 703Y, B119_A, B119_B wireless unit    -   111_A, 111_B, B121_A, B121_B antenna unit #A, antenna unit #B    -   113 control information mapping unit    -   203, B104 error correction encoder    -   205 mapping unit    -   207, 306, B108 processor    -   302 serial/parallel conversion unit    -   304 inverse Fourier transform unit    -   701X, 701Y antenna unit #X, antenna unit #Y    -   705_1, 707_1 modulated signal u1 channel estimating unit    -   705_2, 707_2 modulated signal u2 channel estimating unit    -   709 control information demodulator    -   711, 713 phase noise estimating unit    -   715 signal processing unit    -   B106 modulated signal generator    -   B110_A, B110_B discrete Fourier transform unit    -   B113_A, B113_B subcarrier mapping unit    -   B115_A, B115_B inverse (fast) Fourier transform unit    -   B117_A, B117_B cyclic prefix adding unit

The invention claimed is:
 1. A base station apparatus, comprising: a downlink signal generation circuit, which, in operation, generates a downlink signal including a first data signal for first reception apparatus mapped on a first set of subcarriers and a second data signal for a second reception apparatus mapped on a second set of subcarriers, determines whether to map a first Reference Signal for Phase Tracking (PT-RS) to the first data signal based on a first Modulation and Coding Scheme (MCS) configured for the first data signal, wherein in a case where Phase Shift Keying (PSK) is used as a modulation scheme of the first MCS, the downlink signal generation circuit determines to not map the first PT-RS, determines whether to map a second PT-RS to the second data signal based on a second MCS configured for the second data signal, wherein in a case where PSK is used as a modulation scheme of the second MCS, the downlink signal generation circuit determines to not map the second PT-RS, responsive to determining to map the first PT-RS, maps the first PT-RS to the first data signal for the first reception apparatus, and responsive to determining to map the second PT-RS, maps the second PT-RS to the second data signal for the second reception apparatus; and a transmitter, which is coupled to the downlink signal generation circuit and which, in operation, transmits the downlink signal.
 2. The base station apparatus according to claim 1, wherein whether to map the first PT-RS is determined based on a modulation order of the first MCS, and wherein whether to map the second PT-RS is determined based on a modulation order of the second MCS.
 3. The base station apparatus according to claim 1, wherein, when the first PT-RS is to be mapped, frequency of insertion of the first PT-RS in a time axis, in a frequency axis, or in time and frequency domain depends on the first MCS, and wherein, when the second PT-RS is to be mapped, frequency of insertion of the second PT-RS in the time axis, in the frequency axis, or in time and frequency domain depends on the second MCS.
 4. The base station apparatus according to claim 1, wherein a correction coefficient of transmission power for the first PT-RS and a correction coefficient of transmission power for the first data signal are different from each other, and wherein a correction coefficient of transmission power for the second PT-RS and a correction coefficient of transmission power for the second data signal are different from each other.
 5. The base station apparatus according to claim 1, wherein, in a case where a first modulation order of the first MCS configured for the first data signal for the first reception apparatus is equal to or greater than a threshold value, the downlink signal generation circuit maps the first PT-RS to resources allocated to the first reception apparatus, and in a case where the first modulation order is smaller than the threshold value, the downlink signal generation circuit does not map the first PT-RS to the resources.
 6. A transmission method performed by a base station, comprising: generating a downlink signal including a first data signal for first reception apparatus mapped on a first set of subcarriers and a second data signal for a second reception apparatus mapped on a second set of subcarriers; determining whether to map a first Reference Signal for Phase Tracking (PT-RS) to the first data signal based on a first Modulation and Coding Scheme (MC S) configured for the first data signal, wherein in a case where Phase Shift Keying (PSK) is used as a modulation scheme of the first MCS, the determining includes determining to not map the first PT-RS; determining whether to map a second PT-RS to the second data signal based on a second MCS configured for the second data signal, wherein in a case where PSK is used as a modulation scheme of the second MCS, the determining includes determining to not map the second PT-RS; responsive to determining to map the first PT-RS, mapping the first PT-RS to the first data signal for the first reception apparatus; responsive to determining to map the second PT-RS, mapping the second PT-RS to the second data signal for the second reception apparatus; and transmitting the downlink signal.
 7. The transmission method according to claim 6, wherein whether to map the first PT-RS, is determined based on a modulation order of the first MCS, and wherein whether to map the second PT-RS is determined based on a modulation order of the second MCS.
 8. The transmission method according to claim 6, wherein, when the first PT-RS is to be mapped, frequency of insertion of the first PT-RS in a time axis, in a frequency axis, or in time and frequency domain depends on the first MCS, and wherein, the second PT-RS is to be mapped, frequency of insertion of the second PT-RS in the time axis, in the frequency axis, or in time and frequency domain depends on the second MCS.
 9. The transmission method according to claim 6, wherein a correction coefficient of transmission power for the first PT-RS and a correction coefficient of transmission power for the first data signal are different from each other, and wherein a correction coefficient of transmission power for the second PT-RS and a correction coefficient of transmission power for the second data signal are different from each other.
 10. The transmission method according to claim 6, wherein, when a first modulation order of the first MCS configured for the first data signal for the first apparatus is equal to or greater than a threshold value, the first PT-RS is mapped to resources allocated to the first reception apparatus, and when the modulation order is smaller than the threshold value, the first PT-RS is not mapped to the resources. 